apacheGH-37181: [MATLAB] Remove outdated test class tArrowCppCall.m (…

…apache#37185)

### Rationale for this change

Now that `featherread` and `featherwrite` have been re-implemented in terms of the new APIs (`matlab.internal.io.feather.Reader` in apache#37046 and `matlab.io.internal.feather.Writer` in apache#37045), we can start removing the MEX code. To avoid submitting a large pull request, we should break the work down into several smaller, incremental steps.

The first step should involve deleting the outdated test class `tArrowCppCall.m`. This test class will no longer be relevant once the MEX source code is removed.

### What changes are included in this PR?

1. Deleted the outdated test class `tArrowCppCall.m`

### Are these changes tested?

No tests necessary.

### Are there any user-facing changes?

No.

### Future Directions

1. Move the test cases in `test/tfeathermex.m` to `test/arrow/internal/io/feather/tRoundtrip.m`. These test cases directly call the MEX functions, so we will re-write the tests to utilize the `arrow.internal.io.feather.Reader` and `arrow.internal.io.feather.Writer` classes directly.
2. Delete `test/arrow/util/createVariablesAndMetadataStruct.m`
3. Delete `test/arrow/util/createTable.m`
4. Delete `test/arrow/util/featherMEXRoundTrip.m`
5. Delete `test/arrow/util/featherRoundTrip.m`
6. Remove MEX source code.
* Closes: apache#37181

Authored-by: Sarah Gilmore <sgilmore@mathworks.com>
Signed-off-by: Kevin Gurney <kgurney@mathworks.com>