1. Add extension 'GL_ANGLE_program_binary' to registry_xml.py, this
extension brings enum 'GL_PROGRAM_BINARY_ANGLE' which ANGLE already
supports.
2. Add a fallback for converting GLenum and GLbitfield to string, for
any GLenum value not found in the conversion table, write out its hex
value instead of 'EnumUnknown'. It prevents GLenum from some
unregistered extensions breaking the frame capture.

Bug: angleproject:3804
Change-Id: I36a676305fbbcff2173bbc9f818ff589abe51434
Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/1775028
Commit-Queue: Tobin Ehlis <tobine@google.com>
Reviewed-by: Tobin Ehlis <tobine@google.com>