Fix JDWP IsCollected command handling.

Update the handling of the JDWP IsCollected command for 'null' object id and
invalid object id.

We follow the RI where 'null' object id triggers an INVALID_OBEJCT error but
an invalid object id does not trigger error and return 'true' result.

Also fix handling of 'null' object id to avoid confusion with valid object id.
We used to rely on ObjectRegistry::Get returning NULL to detect null object id
(in which case we return an INVALID_OBJECT error). The issue is this method
may also return NULL for a valid object id if the corresponding object has
been collected. In this case, we must not return any JDWP error and the result
of the command should be 'true' meaning the object identified by the given id
has been collected.

Bug: 12221035
Change-Id: I013f3759bac7cf5b1e9ee3e8c0d1bb2a11f1b654
Run checkpoints after resuming threads in signal catcher SIGQUIT.

Previously we were running checkpoints after restoring the thread
state, but before resuming the threads. This caused an issue with
profiler checkpoints since these use a ScopedObjectAccess. Since
we had with exclusive access to the mutator lock when we ran the
checkpoints, it caused deadlocks when we tried to gain shared
access to the mutator lock in the ScopedThreadStateChange if the
old_state was any state other than kRunnable.

Bug: 12490061
Change-Id: I5f922693a4bf5d18cf9d22f1f28a7a04b6bfc077
Clean up frontend.h includes and forward declarations.

Remove unused and add needed includes and forward
declarations. Explicitly include "invoke_type.h" instead
of relying on indirect inclusion via "dex_file.h".

Change-Id: Ic7a2e0e9a1f29f10008ca42a1183e357d132fd88
Fix bit-rot in clean-oat targets

Change-Id: If7f1681b34284b16ace6bafdacc2a19a3268480c
Mark methods in method_verifier-inl.h as inline.

This allows method_verifier-inl.h to be included from
multiple translation units.

Change-Id: I2f4789b565de3af37dc26d925167551f9e11f132

Conflicts:
	runtime/verifier/method_verifier-inl.h