OpenCL Extended Instruction Set Specification defines relations between
return/operand types and pointee type of pointer arguments in case of
remquo, fract, frexp, lgamma_r, modf, sincos and prefetch instructions
(https://registry.khronos.org/SPIR-V/specs/unified1/OpenCL.ExtendedInstructionSet.100.html).
This PR ensures correct pointee types of those OpenCL Extended
Instructions' pointer arguments.