This change adds basic `MCInst` verification (checks the number of
operands) and fixes detected bugs.
* `RFE*` instructions have only one operand, but `DecodeRFEInstruction`
added two.
* `DecodeMVEModImmInstruction` and `DecodeMVEVCMP` added a `vpred`
operand, but this is what `AddThumbPredicate` normally does. This
resulted in an extra `vpred` operand.
* `DecodeMVEVADCInstruction` added an extra immediate operand.
* `getARMInstruction` added a `pred` operand to instructions that don't
have one (via `DecodePredicateOperand`).
* `AddThumb1SBit` appended an extra register operand to instructions
that don't modify CPSR (such as `tBL`).
* Instructions in `NEONDup` namespace have `pred` operand that the
generated code successfully decodes. The operand was added once again by
`getARMInstruction`/`getThumbInstruction` via `AddThumbPredicate`.
Functional changes extracted from #156540.
4cace1ff0f