Removing redundant stubs for API functions.

src/x64/macro-assembler-x64.h

Index: src/x64/macro-assembler-x64.h
===================================================================
--- src/x64/macro-assembler-x64.h	(revision 5791)
+++ src/x64/macro-assembler-x64.h	(working copy)
@@ -813,14 +813,25 @@
                                  int num_arguments,
                                  int result_size);
 
+  MUST_USE_RESULT MaybeObject* TryTailCallExternalReference(
+      const ExternalReference& ext, int num_arguments, int result_size);
+
   // Convenience function: tail call a runtime routine (jump).
   void TailCallRuntime(Runtime::FunctionId fid,
                        int num_arguments,
                        int result_size);
 
+  MUST_USE_RESULT  MaybeObject* TryTailCallRuntime(Runtime::FunctionId fid,
+                                                   int num_arguments,
+                                                   int result_size);
+
   // Jump to a runtime routine.
   void JumpToExternalReference(const ExternalReference& ext, int result_size);
 
+  // Jump to a runtime routine.
+  MaybeObject* TryJumpToExternalReference(const ExternalReference& ext,
+                                          int result_size);
+
   // Prepares stack to put arguments (aligns and so on).
   // Uses calle-saved esi to restore stack state after call.
   void PrepareCallApiFunction(int stack_space);
@@ -828,7 +839,8 @@
   // Tail call an API function (jump). Allocates HandleScope, extracts
   // returned value from handle and propogates exceptions.
   // Clobbers ebx, edi and caller-save registers.
-  void CallApiFunctionAndReturn(ApiFunction* function);
+  MUST_USE_RESULT MaybeObject* TryCallApiFunctionAndReturn(
+      ApiFunction* function);
 
   // Before calling a C-function from generated code, align arguments on stack.
   // After aligning the frame, arguments must be stored in esp[0], esp[4],