Remove one of the GCs performed by the --gc-greedy flag.  The GC performed by CEntryStub before the first call to C, when --gc-greedy is set, caused a bug in calling API callbacks.
Review URL: http://codereview.chromium.org/171104

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@2706 ce2b1a6d-e550-0410-aec6-3dcde31c8c00