Fix run-jdwp-tests.sh when running against RI.

We were incorrectly trying to pass --toolchain dx instead of
--toolchain javac when running against the RI.

Test: ./art/tools/run-jdwp-tests.sh --mode=jvm
Change-Id: Ie370afd6cb60fbad8e4171b94dd8885f674fface
1 file changed