[InstCombine] Fold and-reduce idiom

[InstCombine] Fold and-reduce idiom

This patch introduces folding of and-reduce idiom and generates code
that is easier to read and which is lest costly in terms of icmp operations.
The folding is
```
  icmp eq (bitcast(icmp ne (lhs, rhs)), 0)
```
into
```
  icmp eq(bitcast(lhs), bitcast(rhs))
```

See PR53419.

Differential Revision: https://reviews.llvm.org/D118317
Reviewed By: lebedev.ri, spatel