Reduce timeout of JDWP tests

This CL sets the timeout of JDWP tests to 10s (instead of the default
timeout of 60s).

This should save up time for continuous testing (~ 3min on host).
Indeed, some tests do wait until the timeout to detect that no reply
(or no event) has been received.

Test: art/tools/run-jdwp-tests.sh --mode=host --variant=X64
Change-Id: Id03c8a1d629e6da551cf8eb405cc79754a363fe0