It seems that TravisCI is experiencing issues in their infra , and
furthermore they have introduced changes in their default environment 
yesterday due to which MySQL installation fails while deploying a simulator
based environment. Due to these issues, TravisCI won't be available for testing
and validation of PRs.
PR authors, this is to share with you so that you're aware and that failing PRs
may not be because of your changes but issues in the CI itself. I'll work on
this as soon as TravisCI's infra is back, and upgrade our Travis build scripts
to compensate for new environment changes.
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