Remove custom timeout from CtsOpenGlPerf2TestCases

Default of 5 minutes is fine; on a properly behaving device, the whole
suite of 9 tests should take around 2 minutes, so this is an OK margin.

Bug: b/115587000
Test: manually tested on Pixel
Change-Id: Ifa47baf1145d7e569fe0ab4f5013f54fafcdaea5
1 file changed