Start a minimal mlir_utils runtime library for testing debugging purposes

Now that MLIR has a standardized StridedMemRef descriptor, it becomes very easy to interact with external library functions and build utilities directly in C++.
This CL introduces basic printing support in a libmlir_utils.so.
Unit tests are rewritten using this feature and also to improve coverage.

For now, C mandates that we have a unique function for each MemRef element type and rank.
In a future a simple unranked descriptor can be introduced to only require uniqu'ing by element type.

PiperOrigin-RevId: 273304741