Change ExecUtils to support callbacks.

artd needs the callbacks to get the pid in order to kill the subprocess.

Partially cherry-picked from
commit 659f49bdb1263ceb26f666052f3ef7e4732b4eb2

Bug: 244412198
Test: m test-art-host-gtest-art_runtime_tests
Merged-In: I8c40949b5ed88ff85ddedad9d86f0b9bbfddb98d
Change-Id: Ia28410bdf6314178756ee5e3a94000dc6f3ecc97
3 files changed