[flang] [clang] [flang] (Re-)Enable alias tags pass by default (PR #74250)

[Tom Eccles via cfe-commits]

tblah wrote:

@banach-space once this is in, I'll remove `-f[no-]alias-analysis` in a separate patch, as it didn't turn out to be as useful for debugging as I expected (the `-mllvm` option is more specific), and as you mentioned - these arguments are non-standard.

https://github.com/llvm/llvm-project/pull/74250