cleanup api callbacks now that handles are never returned directly

src/x64/macro-assembler-x64.h

Index: src/x64/macro-assembler-x64.h
diff --git a/src/x64/macro-assembler-x64.h b/src/x64/macro-assembler-x64.h
index 61abc206e108ec2f85e0ff83393eb778c58dde79..dcbf6aef96e7ed4b0c8435d4e6fa1a2a916adffe 100644
--- a/src/x64/macro-assembler-x64.h
+++ b/src/x64/macro-assembler-x64.h
@@ -1242,7 +1242,7 @@ class MacroAssembler: public Assembler {
   // rcx (rcx must be preserverd until CallApiFunctionAndReturn).  Saves
   // context (rsi).  Clobbers rax.  Allocates arg_stack_space * kPointerSize
   // inside the exit frame (not GCed) accessible via StackSpaceOperand.
-  void PrepareCallApiFunction(int arg_stack_space, bool returns_handle);
+  void PrepareCallApiFunction(int arg_stack_space);
 
   // Calls an API function.  Allocates HandleScope, extracts returned value
   // from handle and propagates exceptions.  Clobbers r14, r15, rbx and
@@ -1252,7 +1252,6 @@ class MacroAssembler: public Assembler {
                                 Address thunk_address,
                                 Register thunk_last_arg,
                                 int stack_space,
-                                bool returns_handle,
                                 int return_value_offset_from_rbp);
 
   // Before calling a C-function from generated code, align arguments on stack.