Remove --stop-at flag from several backends.

test/cctest/heap/test-heap.cc

Index: test/cctest/heap/test-heap.cc
diff --git a/test/cctest/heap/test-heap.cc b/test/cctest/heap/test-heap.cc
index 17143d30c4a742fc6850a71a10de60e13cbda18a..80d3a0e84fe4c4e7a4a4291748b449396a1f22de 100644
--- a/test/cctest/heap/test-heap.cc
+++ b/test/cctest/heap/test-heap.cc
@@ -4214,9 +4214,6 @@ TEST(Regress169209) {
   CHECK(shared1->code()->gc_metadata() != NULL);
 
   // Optimize function and make sure the unoptimized code is replaced.
-#ifdef DEBUG
-  FLAG_stop_at = "f";
-#endif
   CompileRun("%OptimizeFunctionOnNextCall(g);"
              "g(false);");