cmd/vet: bring in pass to catch invalid uses of testing.T in goroutines

Add "go/analysis/passes/testinggoroutine" from x/tools and vendor its source in.
This pass will catch misuses of:
* testing.T.Fail*
* testing.T.Fatal*
* testing.T.Skip*
inside goroutines explicitly started by the go keyword.

The pass was implemented in CL 212920.

While here, found 2 misuses in:
* database/sql/sql_test.go
* runtime/syscall_windows_test.go
and fixed them in CL 235527.

Fixes #5746

Change-Id: I1740ad3f1d677bb5d78dc5d8d66bac6ec287a2b1
Reviewed-on: https://go-review.googlesource.com/c/go/+/235677
Run-TryBot: Emmanuel Odeke <[email protected]>
TryBot-Result: Go Bot <[email protected]>
Reviewed-by: Ian Lance Taylor <[email protected]>
Trust: Emmanuel Odeke <[email protected]>

Author: odeke-em

src/cmd/vendor/golang.org/x/tools/go/analysis/passes/testinggoroutine/testinggoroutine.go

@@ -24,6 +24,7 @@ import (
 	"golang.org/x/tools/go/analysis/passes/stdmethods"
 	"golang.org/x/tools/go/analysis/passes/stringintconv"
 	"golang.org/x/tools/go/analysis/passes/structtag"
+	"golang.org/x/tools/go/analysis/passes/testinggoroutine"
 	"golang.org/x/tools/go/analysis/passes/tests"
 	"golang.org/x/tools/go/analysis/passes/unmarshal"
 	"golang.org/x/tools/go/analysis/passes/unreachable"
@@ -55,6 +56,7 @@ func main() {
 		stringintconv.Analyzer,
 		structtag.Analyzer,
 		tests.Analyzer,
+		testinggoroutine.Analyzer,
 		unmarshal.Analyzer,
 		unreachable.Analyzer,
 		unsafeptr.Analyzer,