Disable inspector-protocol/timeline/page-frames.js on Mac Debug

This test fails on Mac 10.11 Debug since it was added in
https://codereview.chromium.org/2950713002

TBR=dgozman@chromium.org
BUG=734762

Review-Url: https://codereview.chromium.org/2952373002
Cr-Commit-Position: refs/heads/master@{#481826}

third_party/WebKit/LayoutTests/TestExpectations

@@ -2831,3 +2831,5 @@ crbug.com/736177 [ Mac ] virtual/mojo-loading/http/tests/misc/acid2-pixel.html [
 crbug.com/736177 [ Mac ] virtual/off-main-thread-fetch/http/tests/misc/acid2-pixel.html [ Failure Pass ]
 crbug.com/736177 [ Mac ] virtual/prefer_compositing_to_lcd_text/scrollbars/custom-scrollbar-with-incomplete-style.html [ Failure Pass ]
 crbug.com/736177 [ Mac ] virtual/rootlayerscrolls/scrollbars/custom-scrollbar-with-incomplete-style.html [ Failure Pass ]
+
+crbug.com/734762 [ Mac Debug ] inspector-protocol/timeline/page-frames.js [ Failure ]