CMake: fix runtests.pl with CMake, add new test targets

CMake: fix runtests.pl with CMake, add new test targets

  * runtests.pl:
    - Fix out-of-tree build under CMake when srcdir is not set. Default
      srcdir to the location of runtests.pl.
    - Add a hack to allow CMake to use the TFLAGS option as documented
      in tests/README and used in scripts/travis/script.sh.
  * Bump CMake version to 3.2 for USES_TERMINAL, dropping Debian Jessie
    support (no one should care, it is already EOL.).
  * Remove CTest since it defines its own 'test' target with no tests
    since all unittests are already broken and not built by default.
  * Add new test targets based on the options from Makefile.am. Since
    new test targets are rarely added, I opted for duplicating the
    runtests.pl options as opposed to creating a new Makefile.inc file.
    Use top-level target names (test-x) instead of x-test since that is
    used by CI and others.

Closes #5358