WIP: First implementation of serial/fast path.

This showcases the expected performance when a task executes a sub-tree without inference from other threads. We target to stay about 6x slower than a normal function call.
4 jobs from coninuation in 28 seconds (queued for 3 seconds)
Status Job ID Name Coverage
  Build
passed #3379
build_cmake

00:14

 
  Test
failed #3380
run_tests

00:13

 
  Sanitizer
skipped #3382
run_address_sanitizer
skipped #3381
run_thread_sanitizer
 
Test run_tests
-- Build files have been written to: /builds/gitlab/las3/development/scheduling/predictable_parallel_patterns/cmake-build-release
Scanning dependencies of target pls
make[2]: *** No rule to make target 'lib/pls/CMakeFiles/pls.dir/build'. Stop.
CMakeFiles/Makefile2:104: recipe for target 'lib/pls/CMakeFiles/pls.dir/all' failed
make[1]: *** [lib/pls/CMakeFiles/pls.dir/all] Error 2
make: *** [all] Error 2
Makefile:140: recipe for target 'all' failed
./ci_scripts/run_tests.sh: line 9: ./bin/tests: No such file or directory
ERROR: Job failed: exit code 1