MIPS64: Fix 'MIPS: Fix [debug] implement intuitive semantics for stepping over await call.'

Port 941524f8

TEST=mjsunit/harmony/async-debug-*
BUG=

Review-Url: https://codereview.chromium.org/2045923002
Cr-Commit-Position: refs/heads/master@{#36784}

src/mips64/builtins-mips64.cc

@@ -718,7 +718,7 @@ void Builtins::Generate_ResumeGeneratorTrampoline(MacroAssembler* masm) {
   ExternalReference debug_suspended_generator =
       ExternalReference::debug_suspended_generator_address(masm->isolate());
   __ li(a5, Operand(debug_suspended_generator));
-  __ lw(a5, MemOperand(a5));
+  __ ld(a5, MemOperand(a5));
   __ Branch(&prepare_step_in_suspended_generator, eq, a1, Operand(a5));
   __ bind(&stepping_prepared);