Concurrent CSV parsing and reduce S3 select allocations (#8200)

```
CSV parsing, BEFORE:
BenchmarkReaderBasic-12         	    2842	    407533 ns/op	  397860 B/op	     957 allocs/op
BenchmarkReaderReplace-12       	    2718	    429914 ns/op	  397844 B/op	     957 allocs/op
BenchmarkReaderReplaceTwo-12    	    2718	    435556 ns/op	  397855 B/op	     957 allocs/op
BenchmarkAggregateCount_100K-12    	     171	   6798974 ns/op	16667102 B/op	  308077 allocs/op
BenchmarkAggregateCount_1M-12    	      19	  65657411 ns/op	168057743 B/op	 3146610 allocs/op
BenchmarkSelectAll_10M-12    	       1	20882119900 ns/op	2758799896 B/op	41978762 allocs/op

CSV parsing, AFTER:
BenchmarkReaderBasic-12         	    3721	    312549 ns/op	  101920 B/op	     338 allocs/op
BenchmarkReaderReplace-12       	    3776	    318810 ns/op	  101993 B/op	     340 allocs/op
BenchmarkReaderReplaceTwo-12    	    3610	    330967 ns/op	  102012 B/op	     341 allocs/op
BenchmarkAggregateCount_100K-12    	     295	   4149588 ns/op	 3553623 B/op	  103261 allocs/op
BenchmarkAggregateCount_1M-12    	      30	  37746503 ns/op	33827931 B/op	 1049435 allocs/op
BenchmarkSelectAll_10M-12    	       1	17608495800 ns/op	1416504040 B/op	21007082 allocs/op

~ benchcmp old.txt new.txt
benchmark                           old ns/op       new ns/op       delta
BenchmarkReaderBasic-12             407533          312549          -23.31%
BenchmarkReaderReplace-12           429914          318810          -25.84%
BenchmarkReaderReplaceTwo-12        435556          330967          -24.01%
BenchmarkAggregateCount_100K-12     6798974         4149588         -38.97%
BenchmarkAggregateCount_1M-12       65657411        37746503        -42.51%
BenchmarkSelectAll_10M-12           20882119900     17608495800     -15.68%

benchmark                           old allocs     new allocs     delta
BenchmarkReaderBasic-12             957            338            -64.68%
BenchmarkReaderReplace-12           957            340            -64.47%
BenchmarkReaderReplaceTwo-12        957            341            -64.37%
BenchmarkAggregateCount_100K-12     308077         103261         -66.48%
BenchmarkAggregateCount_1M-12       3146610        1049435        -66.65%
BenchmarkSelectAll_10M-12           41978762       21007082       -49.96%

benchmark                           old bytes      new bytes      delta
BenchmarkReaderBasic-12             397860         101920         -74.38%
BenchmarkReaderReplace-12           397844         101993         -74.36%
BenchmarkReaderReplaceTwo-12        397855         102012         -74.36%
BenchmarkAggregateCount_100K-12     16667102       3553623        -78.68%
BenchmarkAggregateCount_1M-12       168057743      33827931       -79.87%
BenchmarkSelectAll_10M-12           2758799896     1416504040     -48.66%
```

```
BenchmarkReaderHuge/97K-12         	    2200	    540840 ns/op	 184.32 MB/s	 1604450 B/op	     687 allocs/op
BenchmarkReaderHuge/194K-12        	    1522	    752257 ns/op	 265.04 MB/s	 2143135 B/op	    1335 allocs/op
BenchmarkReaderHuge/389K-12        	    1190	    947858 ns/op	 420.69 MB/s	 3221831 B/op	    2630 allocs/op
BenchmarkReaderHuge/778K-12        	     806	   1472486 ns/op	 541.61 MB/s	 5201856 B/op	    5187 allocs/op
BenchmarkReaderHuge/1557K-12       	     426	   2575269 ns/op	 619.36 MB/s	 9101330 B/op	   10233 allocs/op
BenchmarkReaderHuge/3115K-12       	     286	   4034656 ns/op	 790.66 MB/s	12397968 B/op	   16099 allocs/op
BenchmarkReaderHuge/6230K-12       	     172	   6830563 ns/op	 934.05 MB/s	16008416 B/op	   26844 allocs/op
BenchmarkReaderHuge/12461K-12      	     100	  11409467 ns/op	1118.39 MB/s	22655163 B/op	   48107 allocs/op
BenchmarkReaderHuge/24922K-12      	      66	  19780395 ns/op	1290.19 MB/s	35158559 B/op	   90216 allocs/op
BenchmarkReaderHuge/49844K-12      	      34	  37282559 ns/op	1369.03 MB/s	60528624 B/op	  174497 allocs/op
```

pkg/s3select/json/testdata/10.json

@@ -0,0 +1,12 @@
+[
+ {
+	 "key_1": "value",
+	 "key_2": "value"
+ }
+]
+[
+	{
+		"key_1": "value2",
+		"key_2": "value3"
+	}
+]

pkg/s3select/json/testdata/11.json

@@ -0,0 +1,8 @@
+"a"
+1
+3.145
+["a"]
+{}
+{
+    "a": 1
+}

pkg/s3select/json/testdata/12.json

@@ -0,0 +1,5 @@
+{
+    "a": 1
+}{
+    "b": 2
+}

pkg/s3select/json/testdata/2.json

@@ -0,0 +1 @@
+{"text": "hello world\\n2nd line"}

pkg/s3select/json/testdata/3.json

@@ -0,0 +1 @@
+{"hello":"wor{l}d"}

pkg/s3select/json/testdata/4.json

@@ -0,0 +1,26 @@
+{
+	"id": "0001",
+	"type": "donut",
+	"name": "Cake",
+	"ppu": 0.55,
+	"batters":
+		{
+			"batter":
+				[
+					{ "id": "1001", "type": "Regular" },
+					{ "id": "1002", "type": "Chocolate" },
+					{ "id": "1003", "type": "Blueberry" },
+					{ "id": "1004", "type": "Devil's Food" }
+				]
+		},
+	"topping":
+		[
+			{ "id": "5001", "type": "None" },
+			{ "id": "5002", "type": "Glazed" },
+			{ "id": "5005", "type": "Sugar" },
+			{ "id": "5007", "type": "Powdered Sugar" },
+			{ "id": "5006", "type": "Chocolate with Sprinkles" },
+			{ "id": "5003", "type": "Chocolate" },
+			{ "id": "5004", "type": "Maple" }
+		]
+}

pkg/s3select/json/testdata/5.json

@@ -0,0 +1,5 @@
+{
+	"foo": {
+		"bar": "baz"
+	}
+}

pkg/s3select/json/testdata/6.json

@@ -0,0 +1 @@
+{ "name": "John", "age":28, "hobby": { "name": "chess", "type": "boardgame" }}

pkg/s3select/json/testdata/7.json

@@ -0,0 +1,3 @@
+{"name":"Michael", "age": 31}
+{"name":"Andy", "age": 30}
+{"name":"Justin", "age": 19}

pkg/s3select/json/testdata/8.json

@@ -0,0 +1,2 @@
+{"a":"}"
+}

pkg/s3select/json/testdata/9.json

@@ -0,0 +1,6 @@
+[
+ {
+	 "key_1": "value",
+	 "key_2": "value"
+ }
+]