[PATCH] [libcxxabi] Refactor test timing logic and disable by default.

[Jonathan Roelofs]

LGTM

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Comment at: test/test_demangle.cpp:15
@@ -14,3 +14,3 @@
 #include <cassert>
-#include <chrono>
+#include "support/timer.hpp"
 
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I think this include should go at the top.

http://reviews.llvm.org/D6391