- Added EXPECT_GLENUM_EQ to solve signed/unsigned comparisons
- Added createProgram and drawQuad utility functions to reduce
  code duplication

Change-Id: I8a62110346de501a1a77ec9688cf06b321385661
Reviewed-on: https://swiftshader-review.googlesource.com/17668Tested-by: Alexis Hétu <sugoi@google.com>
Reviewed-by: Alexis Hétu <sugoi@google.com>