CI - Enable parallelized test runs in coverage test

Basic Info

• Related issues: #830 (closed)
• Requested reviewers: @kiene

Reason why this change is needed

• Parallelizing the the code coverage tests so that they run faster.

Description of the change

• Added new cflags to cmake and the standalone Makefile to ensure multi-threaded test runs produce the same results as single threaded. Also updated the smoke test script and ci yaml so that the tests run in parallel.

Affected operating points

• As this is a CI change it is BE.