PSA: flaky test bug on UBSan bot

[Fergal Daly]

Over the last few days, LUCI analysis bug bot has been filing bugs for flaky tests that are already fixed. A change was submitted that caused many (100s) of tests to appear flaky. The change was reverted but the bug bot filed hundreds of bugs and might still be filing them.

If you see a bug where the failure is as below, you can mark it as a dup of https://crbug.com/453680461 . Hopefully there will be some automated cleanup to take care of these bugs. https://crbug.com/454223159 is tracking the more general issue.

F

[907071:907071:WARNING:content/browser/renderer_host/render_frame_host_impl.cc:3734] Creating unbound remote associated interface provider
../../content/browser/web_contents/web_contents_impl.cc:7351:5: runtime error: downcast of address 0x07ac002241e0 which does not point to an object of type 'RenderProcessHostImpl'
0x07ac002241e0: note: object is of type 'content::MockRenderProcessHost'
 00 00 00 00  70 11 6d 76 f9 5d 00 00  38 15 6d 76 f9 5d 00 00  20 13 5d 00 ac 07 00 00  00 ad db ba
              ^~~~~~~~~~~~~~~~~~~~~~~
              vptr for 'content::MockRenderProcessHost'
    #0 0x5df9664ca993 in content::WebContentsImpl::ReadyToCommitNavigation(content::NavigationHandle*) content/browser/web_contents/web_contents_impl.cc:7351:5

Taken from this bot run.