glsl2: Fix inlining with sampler array or struct dereferences as arguments.

glsl2: Fix inlining with sampler array or struct dereferences as arguments.

Previously, we'd replace an argument of mysampler[2] with a plain
reference to mysampler by using the cloning hash table.  Instead, use
a visitor to clone whatever complicated sampler dereference into the
sampler parameter derefs in the inlined function body.