The address checker records uses in its livenessUses map.  Previously,
that map mapped from an instruction to a range of fields of the type.
But an instruction can use multiple discontiguous fields of a single
value.  Here, such instructions are properly recorded by fixing the map
to store a bit vector for each instruction.

rdar://110676577

```
../include/swift/SIL/FieldSensitivePrunedLiveness.h:531:54: warning: 'hasValue' is deprecated: Use has_value instead. [-Wdeprecated-declarations]
  bool isInitialized() const { return numBitsToTrack.hasValue(); }
                                                     ^~~~~~~~
                                                     has_value
```

[MoveOnlyAddressChecker] Fix representation for used fields.

…1/fix-warning

Gardening: Silenced Optional::hasValue warning.