This fixes a corner-case on ARM and MIPS where optimized code was not
shared immediately across closures when a function was used in several
global contexts at once.

R=ulan@chromium.org
TEST=cctest/test-compiler/OptimizedCodeSharing

Review URL: https://chromiumcodereview.appspot.com/10544205

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@11850 ce2b1a6d-e550-0410-aec6-3dcde31c8c00