Improve the usability of test runner scripts

* First of all, remove the counter-intuitive "OUT_DIR" second
  argument of run-test-suite.sh. This, way, the invocation of the
  script becomes easier to remember:
  `tools/runners/run-test-suite.sh <engine> <testsuite>`
  However, this also means that all output files (lists of
  executed, passed, and failed tests) are generated in the current
  working directory.

* Align the behaviour of run-unittests.sh with the above, i.e.,
  don't try to guess where to put output files but write them in
  the CWD.

* Adapt Makefile to the change in the use of the test runner
  scripts: create and change to "check" directories before invoking
  test runner scripts.

Extras:
* tools/runners/run-test-suite.sh collected fail tests from
  directories twice. This does no harm but is inefficient, thus
  removing.
* tools/runners/run-test-suite.sh was too permissive on the
  contents of test suite list files. Better to accept those lines
  only which really contain paths to JS test files.

JerryScript-DCO-1.0-Signed-off-by: Akos Kiss akiss@inf.u-szeged.hu

tools/runners/run-unittests.sh

@@ -18,10 +18,8 @@
 DIR="$1"
 shift
 
-mkdir -p $DIR/check
-
-UNITTEST_ERROR=$DIR/check/unittests.failed
-UNITTEST_OK=$DIR/check/unittests.passed
+UNITTEST_ERROR=unittests.failed
+UNITTEST_OK=unittests.passed
 
 rm -f $UNITTEST_ERROR $UNITTEST_OK