Revert "Add test coverage for --prerender=disabled switch"
Reason for revert:
Causing crash and invalid write on valgrind bots
> Add test coverage for --prerender=disabled switch
>
> This adds a test to ensure that the disable switch is respected
> by ConfigurePrerender in prerender_field_trial.cc.
>
> BUG=455449
>
> Review URL: https://codereview.chromium.org/
897983003
BUG=457047,455449
TBR=dspell@amazon.com
Review URL: https://codereview.chromium.org/
911763002
Cr-Commit-Position: refs/heads/master@{#315462}