Rebaseline, re-enable integration testing in CI, and fix lua syntax errors

[chapman39]

• [x] Re-enable integration tests in CI
• [x] Match order variable in data/input_files/tests/thermal_solid/thermal_expansion.lua
• [x] Update serac_tests submodule to point at this PR, once it's done: https://github.com/LLNL/serac_tests/pull/21

Some changes are from https://github.com/LLNL/serac/pull/1058

Fixes #1046

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 90.58%. Comparing base (f7323cc) to head (c6c1193).

Additional details and impacted files

```diff @@ Coverage Diff @@ ## develop #1067 +/- ## ======================================== Coverage 90.58% 90.58% ======================================== Files 160 160 Lines 14331 14331 ======================================== Hits 12982 12982 Misses 1349 1349 ```

:umbrella: View full report in Codecov by Sentry.
:loudspeaker: Have feedback on the report? Share it here.