Add tsan support to v8's gyp and test driver.

tools/run-tests.py

Index: tools/run-tests.py
diff --git a/tools/run-tests.py b/tools/run-tests.py
index 1077c3e534a69f029c669dffe7a72801e340d80b..d1eb3a339171f3281171c21ac495da890d3f3553 100755
--- a/tools/run-tests.py
+++ b/tools/run-tests.py
@@ -213,6 +213,9 @@ def BuildOptions():
                     default=False, action="store_true")
   result.add_option("-t", "--timeout", help="Timeout in seconds",
                     default= -1, type="int")
+  result.add_option("--tsan",
+                    help="Regard test expectations for TSAN",
+                    default=False, action="store_true")
   result.add_option("-v", "--verbose", help="Verbose output",
                     default=False, action="store_true")
   result.add_option("--valgrind", help="Run tests through valgrind",
@@ -275,6 +278,9 @@ def ProcessOptions(options):
   if options.asan:
     options.extra_flags.append("--invoke-weak-callbacks")
 
+  if options.tsan:
+    VARIANTS = ["default"]
+
   if options.j == 0:
     options.j = multiprocessing.cpu_count()
 
@@ -459,6 +465,7 @@ def Execute(arch, mode, args, options, suites, workspace):
     "simulator_run": simulator_run,
     "simulator": utils.UseSimulator(arch),
     "system": utils.GuessOS(),
+    "tsan": options.tsan,
   }
   all_tests = []
   num_tests = 0