Disable Pnacl browser tests on Linux ASan

They're all very flaky.

TBR=dschuff@chromium.org

Bug: 1003259
Change-Id: Ibf8bd420fd9948ff1a0872df1778958c39759361
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2236143Reviewed-by: Marc Treib <treib@chromium.org>
Commit-Queue: Marc Treib <treib@chromium.org>
Cr-Commit-Position: refs/heads/master@{#776541}

chrome/test/nacl/nacl_browsertest_util.h

@@ -172,6 +172,9 @@ class NaClBrowserTestGLibcExtension : public NaClBrowserTestGLibc {
 // https://code.google.com/p/chromium/issues/detail?id=177555
 #if (defined(OS_WIN) && !defined(NDEBUG))
 #  define MAYBE_PNACL(test_name) DISABLED_##test_name
+#elif defined(OS_LINUX) && defined(ADDRESS_SANITIZER)
+// NaClBrowserTestPnacl tests are very flaky on ASan, see crbug.com/1003259.
+#  define MAYBE_PNACL(test_name) DISABLED_##test_name
 #else
 #  define MAYBE_PNACL(test_name) test_name
 #endif