[release-branch.go1.17] runtime: call testenv.MustHaveCGO in a couple of tests

For #51695
Fixes #51696

Change-Id: Icfe9d26ecc28a7db9040d50d4661cf9e8245471e
Reviewed-on: https://go-review.googlesource.com/c/go/+/392916
Trust: Ian Lance Taylor <[email protected]>
Run-TryBot: Ian Lance Taylor <[email protected]>
TryBot-Result: Gopher Robot <[email protected]>
Reviewed-by: Bryan Mills <[email protected]>
(cherry picked from commit 2d32594)
Reviewed-on: https://go-review.googlesource.com/c/go/+/393698
Reviewed-by: Emmanuel Odeke <[email protected]>

Author: ianlancetaylor

src/runtime/signal_windows_test.go

@@ -25,6 +25,7 @@ func TestVectoredHandlerDontCrashOnLibrary(t *testing.T) {
 		t.Skip("this test can only run on windows/amd64")
 	}
 	testenv.MustHaveGoBuild(t)
+	testenv.MustHaveCGO(t)
 	testenv.MustHaveExecPath(t, "gcc")
 	testprog.Lock()
 	defer testprog.Unlock()
@@ -149,6 +150,7 @@ func TestLibraryCtrlHandler(t *testing.T) {
 		t.Skip("this test can only run on windows/amd64")
 	}
 	testenv.MustHaveGoBuild(t)
+	testenv.MustHaveCGO(t)
 	testenv.MustHaveExecPath(t, "gcc")
 	testprog.Lock()
 	defer testprog.Unlock()