A64: Don't use a 'debug' instruction to implement the 'trace_sim' option.

src/a64/code-stubs-a64.cc

Index: src/a64/code-stubs-a64.cc
diff --git a/src/a64/code-stubs-a64.cc b/src/a64/code-stubs-a64.cc
index 8a62bf3e97ca3b48f26706c3a99e202c6ad9da94..d444fa4700d23767c21482b7cd053a3e16bd5e69 100644
--- a/src/a64/code-stubs-a64.cc
+++ b/src/a64/code-stubs-a64.cc
@@ -2909,12 +2909,6 @@ void JSEntryStub::GenerateBody(MacroAssembler* masm, bool is_construct) {
   ASSERT(jssp.Is(__ StackPointer()));
   Register code_entry = x0;
 
-  // TODO(all): We shouldn't emit debug instructions unconditionally since they
-  // will not work outside the simulator. We need to rethink how these commands
-  // interact with --trace-sim. For now, though, this turns on instruction
-  // tracing _if_ --trace-sim is specified.
-  __ Debug("TRACE ENTRY", 0, TRACE_ENABLE | LOG_ALL);
-
   // Enable instruction instrumentation. This only works on the simulator, and
   // will have no effect on the model or real hardware.
   __ EnableInstrumentation();