Disable ThreadDelegatePosixTest.CurrentThreadBase on ChromeOS

The test has been flaky since it was introduced. See bug for details.

TBR=ssid@chromium.org

Bug: 1133434
Change-Id: I7ecb38170912745d7b86fc3128b1601c8e6537e6
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2438969Reviewed-by: Yi Gu <yigu@chromium.org>
Commit-Queue: Yi Gu <yigu@chromium.org>
Cr-Commit-Position: refs/heads/master@{#811854}

base/profiler/thread_delegate_posix_unittest.cc

@@ -11,7 +11,8 @@
 namespace base {
 
 // ASAN moves local variables outside of the stack extents.
-#if defined(ADDRESS_SANITIZER)
+// Test is flaky on ChromeOS. crbug.com/1133434.
+#if defined(ADDRESS_SANITIZER) || defined(OS_CHROMEOS)
 #define MAYBE_CurrentThreadBase DISABLED_CurrentThreadBase
 #else
 #define MAYBE_CurrentThreadBase CurrentThreadBase