[MLIR][Presburger] fourier-motzkin: check if all LCMs are 1 using a bool instead...

[MLIR][Presburger] fourier-motzkin: check if all LCMs are 1 using a bool instead of by multiplying them

This can easily overflow and it is possible for these unsigned overflows to result in incorrect results.
For example, the two LCMs could be 641 and 6700417, which multiply to 2^32 + 1, which overflows to 1.
Unsigned overflows already occur in the existing tests.

Also, when switching to arbitrary-precision arithmetic, this results in a many
large integer multiplications resulting in a significant slowdown.

Reviewed By: Groverkss

Differential Revision: https://reviews.llvm.org/D131184