[PATCH] tsan: automatically deflake flaky tests

[Alexey Samsonov]

LGTM with a nit

================
Comment at: test/tsan/lit.cfg:60
@@ -59,1 +59,3 @@
 
+config.substitutions.append( ("%deflake ", "$(dirname %s)/deflake.bash ") )
+
----------------
  os.path.join(os.path.dirname(__file__), "deflake.bash")

http://reviews.llvm.org/D3913