Fix debugger disconnection crash.
Fix debugger disconnection crash.

Fixes a check failure where we uninstall instrumentation while we did not
install it before. This happens when the JDWP thread stops with no debugger
connected.

Bug: 13168905
Change-Id: I83766ced79721747e5a7aaf27ce01a853ad55f03

treadstoneproject/artinst,treadstoneproject/artinst,treadstoneproject/artinst,treadstoneproject/artinst,treadstoneproject/artinst