Suppress data races in crash_reporter::InitializeCrashKeys()

BUG=794920
TBR=rsesek@chromium.org

Change-Id: I3ea15492e4f08a0879fdd0c5476a09bcf5db6836
Reviewed-on: https://chromium-review.googlesource.com/970477Reviewed-by: Alexander Potapenko <glider@chromium.org>
Reviewed-by: Robert Sesek <rsesek@chromium.org>
Commit-Queue: Alexander Potapenko <glider@chromium.org>
Cr-Commit-Position: refs/heads/master@{#544381}

build/sanitizers/tsan_suppressions.cc

@@ -255,6 +255,9 @@ char kTSanDefaultSuppressions[] =
     "race:base::i18n::IsRTL\n"
     "race:base::i18n::SetICUDefaultLocale\n"
 
+    // https://crbug.com/794920
+    "race:crash_reporter::InitializeCrashKeys\n"
+
     // http://crbug.com/795110
     "race:third_party/fontconfig/*\n"