ANY_SAMPLES_PASSED and ANY_SAMPLES_PASSED_CONSERVATIVE queries can not
be active at the same time. The only place where the
State::isQueryActive function is used is validating whether a
BeginQuery call is correct, so it can be changed to check for this.

BUG=angleproject:1101
TEST=dEQP-GLES3.functional.negative_api.fragment.begin_query

Change-Id: Idadf129c6a036570f6e28857bdb24ffc11eeebe8
Reviewed-on: https://chromium-review.googlesource.com/356363Reviewed-by: Jamie Madill <jmadill@chromium.org>
Commit-Queue: Olli Etuaho <oetuaho@nvidia.com>