Add HHVM-specific phpunit configuration

- Up the timeout
- No selenium testing
- No coverage

Also update Travis and build.xml to support it

Signed-off-by: Jeff Chan <jefftchan@gmail.com>

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Note: Adding this because HHVM in JIT mode has extra penalty at first (~50% slow down) -- it's not reasonable to change the timeouts for all individual tests when they're not failing on normal Zend PHP. The alternative is to just change increase the timeouts in `phpunit.xml`, rather than creating another config file (this PR)