Add translation of ptrtoaddr (#3619)
clang start generating the instruction, especially after
llvm/llvm-project@34a61e3
The patch lowers ptrtoaddr to OpConvertPtrToU as:
1. In SPIR-V there are no 'fat pointers', for which ptrtoint and
ptrtoaddr would be different;
2. in Physical addressing model (without 'fat pointers') widths of the
pointers is identical.
Fixes: https://github.com/KhronosGroup/SPIRV-LLVM-Translator/issues/3617
Original commit:
https://github.com/KhronosGroup/SPIRV-LLVM-Translator/commit/9223610cb8c1b34
