Ensure gtest random and seed flags are passed to child test processes.

BUG=1015204

Change-Id: Id63ee4da3c8e51db06da0a306e90adeef7f5618a
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1866972Reviewed-by: Erik Chen <erikchen@chromium.org>
Commit-Queue: Will Harris <wfh@chromium.org>
Cr-Commit-Position: refs/heads/master@{#707419}

base/test/launcher/test_launcher.cc

@@ -238,8 +238,6 @@ CommandLine PrepareCommandLineForGTest(const CommandLine& command_line,
   // Handled by the launcher process.
   switches.erase(kGTestRepeatFlag);
   switches.erase(kIsolatedScriptTestRepeatFlag);
-  switches.erase(kGTestShuffleFlag);
-  switches.erase(kGTestRandomSeedFlag);
 
   // Don't try to write the final XML report in child processes.
   switches.erase(kGTestOutputFlag);