[profiler] Ensure the SafeStackFrameIterator progresses.

If it does not, the stack may be in an unconsistent state. Bailout if so.

BUG=chromium:828881

Change-Id: Ia66077d3846bf9a1d556a37fd8e0ca856f9d2464
Reviewed-on: https://chromium-review.googlesource.com/1002535Reviewed-by: Yang Guo <yangguo@chromium.org>
Commit-Queue: Alexei Filippov <alph@chromium.org>
Cr-Commit-Position: refs/heads/master@{#52532}

src/frames.cc

@@ -297,7 +297,7 @@ void SafeStackFrameIterator::AdvanceOneFrame() {
   if (!frame_) return;
 
   // Check that we have actually moved to the previous frame in the stack.
-  if (frame_->sp() < last_sp || frame_->fp() < last_fp) {
+  if (frame_->sp() <= last_sp || frame_->fp() <= last_fp) {
     frame_ = nullptr;
   }
 }