Implement FEAT_MTE4

QEMU AArch64 introduced FEAT_MTE3 support since 6.1, but ARM released Enhanced Memory Tagging Extension aka FEAT_MTE4 in 2022. Apple uses it in its Memory Integrity Enforcement.

According to ARM's documentation:

FEAT_MTE4 introduces support for the following sub-features:
- Canonical tag checking, identified as FEAT_MTE_CANONICAL_TAGS.
- Reporting of all non-address bits on a fault, identified as FEAT_MTE_TAGGED_FAR.
- Store-only Tag checking, identified as FEAT_MTE_STORE_ONLY.
- Memory tagging with Address tagging disabled, identified as FEAT_MTE_NO_ADDRESS_TAGS.

Do we plan to implement this feature set in QEMU?

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