lock: improve locker initialization at init (#8776)

Use reference format to initialize lockers
during startup, also handle `nil` for NetLocker
in dsync and remove *errorLocker* implementation

Add further tuning parameters such as

 - DialTimeout is now 15 seconds from 30 seconds
 - KeepAliveTimeout is not 20 seconds, 5 seconds
   more than default 15 seconds
 - ResponseHeaderTimeout to 10 seconds
 - ExpectContinueTimeout is reduced to 3 seconds
 - DualStack is enabled by default remove setting
   it to `true`
 - Reduce IdleConnTimeout to 30 seconds from
   1 minute to avoid idleConn build up

Fixes #8773

Dockerfile.simpleci

@@ -34,11 +34,13 @@ USER ci
 RUN make
 RUN bash -c 'diff -au <(gofmt -s -d cmd) <(printf "")'
 RUN bash -c 'diff -au <(gofmt -s -d pkg) <(printf "")'
-RUN for d in $(go list ./... | grep -v browser); do go test -v -race --timeout 20m "$d"; done
-RUN make verifiers
+RUN make test-race
 RUN make crosscompile
 RUN make verify
 
+## -- add healing tests
+RUN make verify-healing
+
 #-------------------------------------------------------------
 # Stage 2: Test Frontend
 #-------------------------------------------------------------