Enable irt=1 for bitcode x86-64
Enable irt=1 for bitcode x86-64

With rev 6279 we are working around
http://code.google.com/p/nativeclient/issues/detail?id=1902
in a different way now.  So we can stop disabling irt=1 mode.

BUG= cleanup
TEST= trybots

R=jvoung@google.com

Review URL: http://codereview.chromium.org/7551029

git-svn-id: 721b910a23eff8a86f00c8fd261a7587cddf18f8@6298 fcba33aa-ac0c-11dd-b9e7-8d5594d729c2

nacl-webkit/native_client,nacl-webkit/native_client,nacl-webkit/native_client,sbc100/native_client,nacl-webkit/native_client,sbc100/native_client,sbc100/native_client,sbc100/native_client,sbc100/native_client,sbc100/native_client,nacl-webkit/native_client