Remove the gl+d3d-only build of the translator This was done at a time where the spir-v generator used glslang and added significant binary size. Bug: chromium:371512561 Change-Id: I6cc733e51f8af555d20181a328b4fbeba6c053c3 Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/5971194 Reviewed-by: Geoff Lang <geofflang@chromium.org> Commit-Queue: Shahbaz Youssefi <syoussefi@chromium.org>