When I originally added the compute assert I used the wrong
documentation. This addresses that.

The dispatch register was tested with homebrew against hardware and is
triggered by some games (e.g. Super Mario Odyssey). What exactly is
missing to get a valid program bound by this engine requires more
investigation.

Co-Authored-By: ReinUsesLisp <reinuseslisp@airmail.cc>

Co-Authored-By: ReinUsesLisp <reinuseslisp@airmail.cc>

Co-Authored-By: ReinUsesLisp <reinuseslisp@airmail.cc>

i965 (and probably all mesa drivers) require GL_PROGRAM_SEPARABLE when using
glProgramBinary. This is probably required by the standard but it's ignored by
permisive proprietary drivers.

Converts many of the Find* functions to return a std::optional<T> as
opposed to returning the raw return values directly. This allows
removing a few assertions and handles error cases like the service
itself does.

This member function doesn't actually modify instance state, so it can
be marked as a const member function.

This was missed within #2075. Renames the member function to make it
consistent with the rest of the Find* functions.