MPS Reader Tests: Test basic feed-get-commit-reclaim cycle

This commit adds an MPS unit test suite `test_suite_mps` which will
subsequently be populated with unit tests for all components of MPS.

As a start, a test case

```
   mbedtls_mps_reader_no_pausing_single_step_single_round()
```

is added which exercises the most basic usage of the MPS reader
component; see the test case description for more details.

Signed-off-by: Hanno Becker <hanno.becker@arm.com>
diff --git a/tests/suites/test_suite_mps.data b/tests/suites/test_suite_mps.data
new file mode 100644
index 0000000..ba89582
--- /dev/null
+++ b/tests/suites/test_suite_mps.data
@@ -0,0 +1,5 @@
+MPS Reader: Single step, single round, pausing disabled
+mbedtls_mps_reader_no_pausing_single_step_single_round:0
+
+MPS Reader: Single step, single round, pausing enabled but unused
+mbedtls_mps_reader_no_pausing_single_step_single_round:1