Clean up build trip count analysis method - avoid mutating IR

- NFC - on any pass/utility logic/output.

- Resolve TODO; the method building loop trip count maps was
  creating and deleting affine.apply ops (transforming IR from under
  analysis!, strictly speaking). Introduce AffineValueMap::difference to
  do this correctly (without the need to create any IR).

- Move AffineApplyNormalizer out so that its methods are reusable from
  AffineStructures.cpp; add a helper method 'normalize' to it. Fix
  AffineApplyNormalize::renumberOneDim (Issue tensorflow/mlir#89).

- Trim includes on files touched.

- add test case on a scenario previously not covered

Signed-off-by: Uday Bondhugula <uday@polymagelabs.com>

Closes tensorflow/mlir#133

COPYBARA_INTEGRATE_REVIEW=https://github.com/tensorflow/mlir/pull/133 from bondhugula:trip-count-build 7fc34d857f7788f98b641792cafad6f5bd50e47b
PiperOrigin-RevId: 269101118