Prevent test colision when running in parallel via RESOURCE_LOCK

[marty1885]

Hi, while working with jsoncpp I noticed that jsoncpp's tests fails if it's running in parallel via ctest -j. See the following logs for detail

❯ ctest -j
Test project /home/marty/Documents/not-my-projects/jsoncpp/build
    Start 2: jsoncpp_readerwriter_json_checker
    Start 1: jsoncpp_readerwriter
    Start 3: jsoncpp_test
1/3 Test #3: jsoncpp_test ........................   Passed    0.01 sec
2/3 Test #2: jsoncpp_readerwriter_json_checker ...***Failed    0.27 sec
3/3 Test #1: jsoncpp_readerwriter ................   Passed    0.60 sec

67% tests passed, 1 tests failed out of 3

Total Test time (real) =   0.61 sec

The following tests FAILED:
          2 - jsoncpp_readerwriter_json_checker (Failed)
Errors while running CTest
Output from these tests are in: /home/marty/Documents/not-my-projects/jsoncpp/build/Testing/Temporary/LastTest.log
Use "--rerun-failed --output-on-failure" to re-run the failed cases verbosely.

The root cause seems to be that both tests writes to the same output/intermid file and colides. ctest by default is single-threaded thus hiding this bug.

This PR fixes the problem by setting RESOURCE_LOCK to serialize the tests even when ctest is instructed to run parallel.