Add conformance2/uniforms/uniform-block-idents-as-expr.

[kdashg]

Fixes #3644.

Fails 4-6 subtests on top-of-tree Chrome and Firefox.

[kdashg]

(I only tested on Windows)

[kenrussell]

Thanks very much Kelsey for putting this together. On current Chromium, the failing cases are:

test[13]: {"programOk":false,"vsrc":"uniform BlockName { vec4 member; } InstanceName;\nvoid f() { InstanceName; }","fsrc":""}
FAIL Expected linked: false, was true

test[14]: {"programOk":false,"vsrc":"","fsrc":"uniform BlockName { vec4 member; } InstanceName;\nvoid f() { InstanceName; }"}
FAIL Expected linked: false, was true

test[23]: {"programOk":false,"vsrc":"uniform BlockName { vec4 member; } InstanceName[1];\nvoid f() { InstanceName; }","fsrc":""}
FAIL Expected linked: false, was true

test[24]: {"programOk":false,"vsrc":"","fsrc":"uniform BlockName { vec4 member; } InstanceName[1];\nvoid f() { InstanceName; }"}
FAIL Expected linked: false, was true

test[27]: {"programOk":false,"vsrc":"uniform BlockName { vec4 member; } InstanceName[1];\nvoid f() { InstanceName[0]; }","fsrc":""}
FAIL Expected linked: false, was true

test[28]: {"programOk":false,"vsrc":"","fsrc":"uniform BlockName { vec4 member; } InstanceName[1];\nvoid f() { InstanceName[0]; }"}
FAIL Expected linked: false, was true

What would be needed to pass these? Does ANGLE's shader translator need to fail compilation of these vertex / fragment shaders? Is more complex validation needed at link time?

[kkinnunen-apple]

Thank you.

[kenrussell]

Thanks Kelsey for the test.