Use java.lang.Process.pid() to get the PID of a process in Vogar.

We used to use reflection to access field `pid` of the `Process`
object, but this started to trigger warnings from the execution
environment lately. Instead, use java.lang.Process.pid(), which is
available since Java 9.

Test: m vogar
Test: m vogar-tests \
      && java -cp "$ANDROID_HOST_OUT/framework/vogar-tests.jar" \
           org.junit.runner.JUnitCore vogar.AllTests
Test: art/tools/buildbot-build.sh --host && \
      art/tools/run-libcore-tests.sh --mode=host --variant=X64
Bug: 143805136
Change-Id: If6c87607eee8c3ec4d0003eb76c7e390fd924e74
1 file changed