[PATCH 00/23] aarch64: Split up QLF_NIL meanings, and other fixes

[Alice Carlotti]

The main goal of this series is to split up the separate meanings of
AARCH64_OPND_QLF_NIL into four operand qualifiers - the existing NIL and ERR
qualifiers, and new UNKNOWN and UNUSED qualifiers.  This means we no longer
need the F_STRICT opcode flag to differentiate between the NIL and UNKNOWN
meanings.  These changes are in patches 18-22.

Patches 2, 6 and 13-17 are prerequisites for the NIL/UNUSED split.

Patch 23 adds checks to enforce correct qualifier sequence lengths.  This would
detect all the issues address in patches 13-17.

Patch 12 fixes an "assert on invalid input" bug.

The other patches are miscellaneous code quality improvements.

I intend to commit this next week if there are no issues raised.

Alice