Change tsan integration to not 'cache' fibers.

We fixed the bug in tsan causing it to crash after creating/deleting many fibers, because of that there is no need for this cache mechanism (you have to use the most recent clang build with the patch for it to work thought).
4 jobs from coninuation in 37 seconds (queued for 6 seconds)
Status Job ID Name Coverage
  Build
passed #3569
build_cmake

00:20

 
  Test
failed #3570
run_tests

00:17

 
  Sanitizer
skipped #3572
run_address_sanitizer
skipped #3571
run_thread_sanitizer
 
Test run_tests
compilation terminated.
app/invoke_parallel/CMakeFiles/invoke_parallel.dir/build.make:62: recipe for target 'app/invoke_parallel/CMakeFiles/invoke_parallel.dir/main.cpp.o' failed
make[2]: *** [app/invoke_parallel/CMakeFiles/invoke_parallel.dir/main.cpp.o] Error 1
CMakeFiles/Makefile2:450: recipe for target 'app/invoke_parallel/CMakeFiles/invoke_parallel.dir/all' failed
make[1]: *** [app/invoke_parallel/CMakeFiles/invoke_parallel.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