cmd/go: temporarily disable build JSON in test output

Unfortunately, this is tripping up the LUCI test output processor, so
we need to disable it until we can figure that out.

For #70402.
Updates #62067.

Cq-Include-Trybots: luci.golang.try:gotip-darwin-arm64_13,gotip-linux-amd64-longtest
Change-Id: I9ae722218e98b8060b8b4c46358f23381ac8537a
Reviewed-on: https://go-review.googlesource.com/c/go/+/628955
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Cherry Mui <cherryyz@google.com>

src/cmd/go/internal/test/testflag.go

@@ -6,7 +6,6 @@ package test
 
 import (
 	"cmd/go/internal/base"
-	"cmd/go/internal/cfg"
 	"cmd/go/internal/cmdflag"
 	"cmd/go/internal/work"
 	"errors"
@@ -355,7 +354,8 @@ func testFlags(args []string) (packageNames, passToTest []string) {
 		delete(addFromGOFLAGS, "v")
 		delete(addFromGOFLAGS, "test.v")
 
-		cfg.BuildJSON = true
+		// TODO(austin,#70402): Re-enable this once LUCI can handle build JSON in the test stream.
+		//cfg.BuildJSON = true
 	}
 
 	// Inject flags from GOFLAGS before the explicit command-line arguments.

src/cmd/go/testdata/script/test_json_build.txt

@@ -1,3 +1,6 @@
+# TODO(austin,#70402)
+skip
+
 [short] skip
 
 # Test a build error directly in a test file.