[llvm] [Analysis] Add Scalable field in MemoryLocation.h (PR #65759)

[David Green via llvm-commits]

https://github.com/davemgreen commented:

Is it worth adding a isScalable check to this line in Attributors getKnownNonNullAndDerefBytesForUse:
```
if (!Loc || Loc->Ptr != UseV || !Loc->Size.isPrecise() || I->isVolatile())
```

https://github.com/llvm/llvm-project/pull/65759