Fix JSON parser handling for certain objects (#7162)

This PR also adds some comments and simplifies
the code. Primary handling is done to ensure
that we make sure to honor cached buffer.

Added unit tests as well

Fixes #7141

pkg/s3select/json/data/10.json

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

pkg/s3select/json/data/11.json

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

pkg/s3select/json/data/12.json

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

pkg/s3select/json/data/2.json

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

pkg/s3select/json/data/3.json

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

pkg/s3select/json/data/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/data/5.json

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

pkg/s3select/json/data/6.json

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

pkg/s3select/json/data/7.json

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

pkg/s3select/json/data/8.json

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

pkg/s3select/json/data/9.json

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