[ABI] Add IndirectAliased kind to abi::ArgInfo (#225005)
Changes:
- Mirror `clang::CodeGen::ABIArgInfo::IndirectAliased:` an indirect
argument whose pointer may alias an object referenced elsewhere and is
never byval.
- Add the kind, a `getIndirectAliased` factory, an `isIndirectAliased`
predicate, and widens the indirect align/addrspace/realign accessors to
both kinds.
- Add unit tests in FunctionInfoTest.
Relates to : https://github.com/llvm/llvm-project/issues/220471
Assisted by: claude opsu 4.8
