[es6] Don't disable ES6 tail call elimination when Debugger is on.

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 a1762fa3544858983bdb8cbfe4dc0fce71de1a35..5fdc7d1f832f573b6467f455cfe6ad5e16ae5381 100644
--- a/src/arm/builtins-arm.cc
+++ b/src/arm/builtins-arm.cc
@@ -1933,15 +1933,6 @@ void PrepareForTailCall(MacroAssembler* masm, Register args_reg,
   DCHECK(!AreAliased(args_reg, scratch1, scratch2, scratch3));
   Comment cmnt(masm, "[ PrepareForTailCall");
 
-  // Prepare for tail call only if the debugger is not active.
-  Label done;
-  ExternalReference debug_is_active =
-      ExternalReference::debug_is_active_address(masm->isolate());
-  __ mov(scratch1, Operand(debug_is_active));
-  __ ldrb(scratch1, MemOperand(scratch1));
-  __ cmp(scratch1, Operand(0));
-  __ b(ne, &done);
-
   // Drop possible interpreter handler/stub frame.
   {
     Label no_interpreter_frame;
@@ -1985,7 +1976,6 @@ void PrepareForTailCall(MacroAssembler* masm, Register args_reg,
   ParameterCount callee_args_count(args_reg);
   __ PrepareForTailCall(callee_args_count, caller_args_count_reg, scratch2,
                         scratch3);
-  __ bind(&done);
 }
 }  // namespace