framework: unify TestPackage behaviour between ES 3.1 and 3.2

framework: unify TestPackage behaviour between ES 3.1 and 3.2

Main issue seen here was that ES 3.2 did not reset context state when
initializing TestCaseWrapper, this was causing different behaviour in
following tests:

  KHR-GLES31.core.draw_buffers_indexed.blending
  KHR-GLES32.core.draw_buffers_indexed.blending

Patch also fixes few other differences spotted.

Components: Framework, OpenGL

VK-GL-CTS issue: 3318

Affects:
   glcts
   cts-runner

Signed-off-by: Tapani Pälli <tapani.palli@intel.com>
Change-Id: Ie5848e41eba64c3b76b526738e8612c8bebdfbfc