[Mesa-dev] V2 RFC initial KHR_no_error support

[Timothy Arceri]

V2: some bug fixes and suggestions addressed as suggested by Brian and
    Nicolai.

This series adds some initial support for the KHR_no_error.

For now it can only be enabled with the MESA_NO_ERROR environment
variable. To start with I've added support to some of the api
calls that were taking a long time (or where caled often) in 
the Civ6 benchmark.