Integrate WebGL SL 1.0 tests from ANGLE

[kenrussell]

Recent work on ANGLE's GLSL ES parser highlighted some missing validation enforcing ESSL 1.00 limitations. Tests have been added to ANGLE which it would be good to port to the WebGL CTS.

https://chromium-review.googlesource.com/c/angle/angle/+/7022355/comment/45aea787_11232be3/

https://chromium-review.googlesource.com/c/angle/angle/+/7022355/comment/c768348e_4bdf6e43/

[kenrussell]

Feedback from WebGL WG: not too concerned about breaking applications, because previous behavior would have been broken, and now will result in a validation error. General consensus that exposing these errors at compile time is better than at run time.

[kenrussell]

Additionally, Mozilla would appreciate tests which cover very simple infinite loop test cases like while (true) { }.