Reland "[mlir][tensor] Support more cases in MergeConsecutiveExtractSlice"

This relands commit 5d4603a0.
It cludes fixes to GCC test failures and simplification to
the implementation.

Co-authored-by: Mahesh Ravishankar <ravishankarm@google.com>
Co-authored-by: Christopher Bate <cbate@nvidia.com>