mesa: Allow Get*() of several forgotten IsEnabled() pnames.

mesa: Allow Get*() of several forgotten IsEnabled() pnames.

From section 6.2 ("State Tables") of the GL 2.1 specification
(the text also appears in the GL 3.0 and ES 3.1 specifications):
"However, state variables for which IsEnabled is listed as the query
 command can also be obtained using GetBooleanv, GetIntegerv, GetFloatv,
 and GetDoublev."

GL_DEBUG_OUTPUT, GL_DEBUG_OUTPUT_SYNCHRONOUS, and GL_FRAGMENT_SHADER_ATI
were missing from the glGet*() functions.  All other IsEnabled() pnames
look to be present, as far as I can tell.

Fixes 8 dEQP-GLES31.functional.debug.state_query subtests:
debug_output[_synchronous]_get{boolean,float,integer,integer64}.

Cc: mesa-stable@lists.freedesktop.org
Signed-off-by: Kenneth Graunke <kenneth@whitecape.org>
Reviewed-by: Ilia Mirkin <imirkin@alum.mit.edu>
Reviewed-by: Emil Velikov <emil.velikov@collabora.com>