cmd/go: retain test binary when go test is run with -mutexprofile

Fixes #18494

Change-Id: I8a190acae6d5f1d20d4e4e4547d84e10e8a7fe68
Reviewed-on: https://go-review.googlesource.com/34793Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>

src/cmd/go/go_test.go

@@ -1885,6 +1885,26 @@ func TestGoTestCpuprofileDashOControlsBinaryLocation(t *testing.T) {
 	tg.wantExecutable("myerrors.test"+exeSuffix, "go test -cpuprofile -o myerrors.test did not create myerrors.test")
 }
 
+func TestGoTestMutexprofileLeavesBinaryBehind(t *testing.T) {
+	tg := testgo(t)
+	defer tg.cleanup()
+	// TODO: tg.parallel()
+	tg.makeTempdir()
+	tg.cd(tg.path("."))
+	tg.run("test", "-mutexprofile", "errors.prof", "errors")
+	tg.wantExecutable("errors.test"+exeSuffix, "go test -mutexprofile did not create errors.test")
+}
+
+func TestGoTestMutexprofileDashOControlsBinaryLocation(t *testing.T) {
+	tg := testgo(t)
+	defer tg.cleanup()
+	// TODO: tg.parallel()
+	tg.makeTempdir()
+	tg.cd(tg.path("."))
+	tg.run("test", "-mutexprofile", "errors.prof", "-o", "myerrors.test"+exeSuffix, "errors")
+	tg.wantExecutable("myerrors.test"+exeSuffix, "go test -mutexprofile -o myerrors.test did not create myerrors.test")
+}
+
 func TestGoTestDashCDashOControlsBinaryLocation(t *testing.T) {
 	tg := testgo(t)
 	defer tg.cleanup()

src/cmd/go/testflag.go

@@ -151,10 +151,10 @@ func testFlags(args []string) (packageNames, passToTest []string) {
 				testBench = true
 			case "timeout":
 				testTimeout = value
-			case "blockprofile", "cpuprofile", "memprofile":
+			case "blockprofile", "cpuprofile", "memprofile", "mutexprofile":
 				testProfile = true
 				testNeedBinary = true
-			case "mutexprofile", "trace":
+			case "trace":
 				testProfile = true
 			case "coverpkg":
 				testCover = true