glsl/es31: precision qualifier doesn't need to match in shader interface block members

glsl/es31: precision qualifier doesn't need to match in shader interface block members

It is specific only to GLSL ES 3.1. From the spec, section 4.3.9
"Interface Blocks":

"Matched block names within a shader interface (as defined above) must
 match in terms of having the same number of declarations with the same
 sequence of types and the same sequence of member names, as well as
 having the same qualification as specified in section 9.2 (“Matching
 of Qualifiers“)."

But in GLSL ES 3.0 and 3.2, it is the opposite:

"Matched block names within a shader interface (as defined above) must
 match in terms of having the same number of declarations with the same
 sequence of types, precisions and the same sequence of member names,
 as well as having the matching member-wise layout qualification as
 defined in section 9.2 (“Matching of Qualifiers”)."

Fixes:

dEQP-GLES31.functional.shaders.linkage.uniform.block.differing_precision

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=98243
Signed-off-by: Samuel Iglesias Gonsálvez <siglesias@igalia.com>
Reviewed-by: Tapani Pälli <tapani.palli@intel.com>