Allow to re-use main thread as worker.

4 jobs from master in 60 minutes 47 seconds (queued for 2 seconds)
Status Job ID Name Coverage
  Build
passed #3144
build_cmake

00:42

 
  Test
failed #3145
run_tests

01:00:04

 
  Sanitizer
skipped #3147
run_address_sanitizer
skipped #3146
run_thread_sanitizer
 
Test run_tests
[ 86%] Linking CXX executable ../../bin/benchmark_matrix
[ 86%] Built target benchmark_matrix
Scanning dependencies of target tests
[ 89%] Building CXX object test/CMakeFiles/tests.dir/main.cpp.o
[ 93%] Building CXX object test/CMakeFiles/tests.dir/data_structures_test.cpp.o
[ 96%] Building CXX object test/CMakeFiles/tests.dir/scheduling_tests.cpp.o
[100%] Linking CXX executable ../bin/tests
[100%] Built target tests
ERROR: Job failed: execution took longer than 1h0m0s seconds