content_browsertests failing on 2 builders

Builders failed on: 
- Cast Audio Linux: 
  https://build.chromium.org/p/chromium.linux/builders/Cast%20Audio%20Linux
- Cast Linux: 
  https://build.chromium.org/p/chromium.linux/builders/Cast%20Linux

The following two tests are segfaulting on Cast Audio Linux and
Cast Linux:

RenderFrameHostManagerSpoofingTest.ShowLoadingURLUntilDocumentOpenSpoof
RenderFrameHostManagerSpoofingTest.ShowLoadingURLUntilSpoof

These were introduced by dcheng in 
https://chromium.googlesource.com/chromium/src/+/3bd0eead2eb6d83f7ccbbd128692731522a1d1f6%5E%21

I'm not sure if we can conditionally disable those bots with
#if or #ifdefs; investigating that now.