Make the direct call to native RegExp work

Single glitch in r3542 which caused the direct call to native regexp code to always bail out to the runtime system.

TBR=erik.corry@gmail.com
Review URL: http://codereview.chromium.org/523091

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@3544 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/ia32/codegen-ia32.cc

@@ -8011,6 +8011,7 @@ void RegExpExecStub::Generate(MacroAssembler* masm) {
   __ j(not_equal, &runtime);
   // Check that the JSArray is in fast case.
   __ mov(ebx, FieldOperand(eax, JSArray::kElementsOffset));
+  __ mov(eax, FieldOperand(ebx, HeapObject::kMapOffset));
   __ cmp(eax, Factory::fixed_array_map());
   __ j(not_equal, &runtime);
   // Check that the last match info has space for the capture registers and the