Remove build check from unit tests

[StephenButtolph]

Why this should be merged

# Check to see if the build script creates any unstaged changes to prevent
# regression where builds go.mod/go.sum files get out of date.
if [[ -z $(git status -s) ]]; then
    echo "Build script created unstaged changes in the repository"
    # TODO: Revise this check once we can reliably build without changes
    # exit 1
fi

-z is used to test that the output is empty. So this check was completely backwards. Additionally, we now have a dedicated test for this as part of the auto-generated code check.

How this works

Simplifies the unit test flow by replacing the call to build_and_test.sh with build_test.sh

How this was tested

CI