runtime: disable GDB tests on AIX with -short

Since the new page allocator, AIX's GDB has trouble running Go programs.
It does work but it can be really slow. Therefore, they are disable when
tests are run with -short.

Updates: #35710

Change-Id: Ibfc4bd2cd9714268f1fe172aaf32a73612e262d6
Reviewed-on: https://go-review.googlesource.com/c/go/+/207919
Run-TryBot: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

src/runtime/runtime-gdb_test.go

@@ -37,6 +37,10 @@ func checkGdbEnvironment(t *testing.T) {
 		}
 	case "freebsd":
 		t.Skip("skipping gdb tests on FreeBSD; see https://golang.org/issue/29508")
+	case "aix":
+		if testing.Short() {
+			t.Skip("skipping gdb tests on AIX; see https://golang.org/issue/35710")
+		}
 	}
 	if final := os.Getenv("GOROOT_FINAL"); final != "" && runtime.GOROOT() != final {
 		t.Skip("gdb test can fail with GOROOT_FINAL pending")