Capture/Replay: Only convert GLES 2 GLenums to string. Previously the enum conversion script would convert all enums in gl.xml including those for desktop GL. When replaying from a CPP file we would sometimes try to use enum values that only are exposed in desktop GL. One example is GL_TEXTURE_MAX_ANISOTROPY/GL_TEXTURE_MAX_ANISOTROPY_EXT. GLES only has the "EXT" version. Desktop uses the core version. This was breaking a replay sample that used the EXT enum. Fix this by a) including the anisotropy extension in registry_xml and b) updating the enum script to only parse GLES 2 entries. In the future we could improve the situation by auto-generating a header that defines exactly the enums we need for ANGLE. Also updates the enum helper to use uppercase enum values. Bug: angleproject:3611 Change-Id: I1e01608bc8af282dc078d5a19ac4eba659c96b57 Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/1894143 Commit-Queue: Jamie Madill <jmadill@chromium.org> Reviewed-by: Tim Van Patten <timvp@google.com>