glsl: Fix structure and array comparisions.

glsl: Fix structure and array comparisions.

We were trying to emit a single ir_expression to compare the whole
thing.  The backends (ir_to_mesa.cpp and brw_fs.cpp so far) expected
ir_binop_any_nequal or ir_binop_all_equal to apply to at most a vector
(with matrices broken down by the lowering pass).  Break them down to
a bunch of ORed or ANDed any_nequals/all_equals.

Fixes:
glsl-array-compare
glsl-array-compare-02
glsl-fs-struct-equal
glsl-fs-struct-notequal
Bug #31909