JDWP: clear exception when allocation fails

Clears pending exception if an allocation (requested by the debugger)
fails and logs an error message about the failure.

Checks we never leave a pending exception after processing a JDWP
request.

Bug: 20037531
Change-Id: I63239034a3c1ab368b0e19c2f5f756d9e2ec6a29
3 files changed