Fix delivering async exception while in compiled code.

Change artInstrumentationMethodExitFromCode() to check
for async exceptions.

Also fix kDebugExceptionDelivery = true causing stale
ObjPtr<> use.

Test: run-test --jit -runtime-option -Xjitthreshold:0 \
      1934-jvmti-signal-thread
Test: Repeat with kDebugExceptionDelivery = true.
Bug: 74583459
Change-Id: Ia2e777cc3ccef4eba549aa290f8bc12608eafe44