Adding test case of element wise addition of dynamic and static memrefs.

In D100077#2687134, @nicolasvasilache wrote:

@mehdi_amini not yet, the author should at the very least set the 2 offsets to 0 to as described in the commit message of https://github.com/google/iree-llvm-sandbox/commit/87015b29c5f7cbc445bd85e1ce4a5d7597e80361, so that it passes without crashing.

I'm fine with iterating in-tree once that is fixed.

Changing the default value of offset to zero.

Redirecting prints to stderr.

Formatting.

Fix itemsize.

Cleaning up.

Remove the memref directory and put files in the parent.

Added support for strided memrefs.

Clean left over.

Python formating.

Minor Changes.