glsl: When doing algebraic simplification, make sure the type still matches.

glsl: When doing algebraic simplification, make sure the type still matches.

When simplifying (vec4(1.0) / (float(x))) to rcp(float(x)), we forgot
to produce a vec4, angering ir_validate when starting alien-arena.

Fixes:
glsl-algebraic-add-zero-2
glsl-algebraic-div-one-2
glsl-algebraic-mul-one-2
glsl-algebraic-sub-zero-3
glsl-algebraic-rcp-sqrt-2