Revert r14252 as it broke --prof for some cases

test/cctest/test-log-stack-tracer.cc

Index: test/cctest/test-log-stack-tracer.cc
diff --git a/test/cctest/test-log-stack-tracer.cc b/test/cctest/test-log-stack-tracer.cc
index 5bfc1d36beef64ef3c34d6229d9b430dac54fa5a..ca6c7aea47bd11f76bc3e10e4f16f7c7174a8453 100644
--- a/test/cctest/test-log-stack-tracer.cc
+++ b/test/cctest/test-log-stack-tracer.cc
@@ -286,7 +286,7 @@ TEST(CFromJSStackTrace) {
   //         DoTrace(EBP) [native]
   //           TickSample::Trace
 
-  CHECK(sample.external_callback);
+  CHECK(sample.has_external_callback);
   CHECK_EQ(FUNCTION_ADDR(TraceExtension::Trace), sample.external_callback);
 
   // Stack tracing will start from the first JS function, i.e. "JSFuncDoTrace"
@@ -336,7 +336,7 @@ TEST(PureJSStackTrace) {
   //             TickSample::Trace
   //
 
-  CHECK(sample.external_callback);
+  CHECK(sample.has_external_callback);
   CHECK_EQ(FUNCTION_ADDR(TraceExtension::JSTrace), sample.external_callback);
 
   // Stack sampling will start from the caller of JSFuncDoTrace, i.e. "JSTrace"