[clang] Fix `remove{CVR|Fast}Qualifiers` with 64-bit `Qualifiers::Mask` (#90329)

After #84384, `Qualifiers::Mask` becomes 64-bit. So, operations like
`Mask &= ~U32` where `U32` is `unsigned` produce undesirable results
since higher 32 bits of `Mask` become zeroed while they should be
preserved. Fix that by explicitly casting `unsigned` values to
`uint64_t` in such operations. Signatures of fixed functions are
intentionally left intact instead of changing the argument itself to
`uint64_t` to keep things consistent with other functions working with
the same qualifiers and to emphasize that 64-bit masks should not be
used for these types of qualifiers.