glsl: don't lower fragdata array if the output data types don't match

glsl: don't lower fragdata array if the output data types don't match

Commit 7e414b58640aee6e243d337e72cea290c354f632 broke the gl_FragData array
into separate gl_FragData[i] variables, so drivers can eliminate useless
writes to gl_FragData improving their performance.

The problem occurs when GLSL IR code is linked in the following case:

* The FS output variable base data type does not match gl_FragData one (float
  vector)
* The FS output variable is replaced by gl_out_FragDataX because of commit
  7e414b58640aee6 with X from 0 to GL_MAX_DRAW_BUFFERS.

Then the FS output variable base data type is lost in the resulting GLSL IR,
making that the driver does a wrong assignment to gl_out_FragData components
because of unmatching data types.

This patch reverts the fragdata array lowering when the output var base data type
doesn't match gl_out_FragData, i.e., when output variable base data type is
not a float or a float vector.

This patch fixes 250 dEQP tests (tested in an Intel Haswell machine)

dEQP-GLES3.functional.fragment_out.random.* (22 failed tests)
dEQP-GLES3.functional.fragment_out.array.uint.* (120 failed tests)
dEQP-GLES3.functional.fragment_out.array.int.* (108 failed tests)

Signed-off-by: Samuel Iglesias Gonsalvez <siglesias@igalia.com>
Reviewed-by: Matt Turner <mattst88@gmail.com>