Remove --stop-at flag from several backends.

src/arm/builtins-arm.cc

Index: src/arm/builtins-arm.cc
diff --git a/src/arm/builtins-arm.cc b/src/arm/builtins-arm.cc
index 4b25aa74248a1b4bcec5120fba03e73f8c6eb221..a82ccfe4b547e7e76edd733435ebd67dd681a8a8 100644
--- a/src/arm/builtins-arm.cc
+++ b/src/arm/builtins-arm.cc
@@ -1039,7 +1039,6 @@ void Builtins::Generate_InterpreterEntryTrampoline(MacroAssembler* masm) {
   // fullcodegen's prologue:
   //  - Support profiler (specifically profiling_counter).
   //  - Call ProfileEntryHookStub when isolate has a function_entry_hook.
-  //  - Allow simulator stop operations if FLAG_stop_at is set.
   //  - Code aging of the BytecodeArray object.
 
   // Load accumulator, register file, bytecode offset, dispatch table into