[asan] Speed up ASan unit tests by turning off symbolication

[kubamracek]

Summary

ASan unit tests don't depend on the symbolizer and they never test its output, but currently they still run it for every crash. This patch simply disables the symbolizer for unit tests, which provides some speed up. On my system (OS X) that's about 1.4x faster, but this could be potentially much more e.g. when using atos on OS X.

[glider]

Good catch, indeed.
LGTM

lib/asan/tests/asan_test_main.cc

 //===-- asan_test_main.cc -------------------------------------------------===//
 //
 //                     The LLVM Compiler Infrastructure
 //
 // This file is distributed under the University of Illinois Open Source
 // License. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
 //
 // This file is a part of AddressSanitizer, an address sanity checker.
 //
 //===----------------------------------------------------------------------===//
 #include "asan_test_utils.h"
 
+// Default ASAN_OPTIONS for the unit tests. Let's turn symbolication off to
+// speed up testing (unit tests don't use it anyway).
+extern "C" const char* __asan_default_options() {
+  return "symbolize=false";
+}
+
 int main(int argc, char **argv) {
   testing::GTEST_FLAG(death_test_style) = "threadsafe";
   testing::InitGoogleTest(&argc, argv);
   return RUN_ALL_TESTS();
 }