ART: Optimize catch phi creation to save memory.

Catch phis are eagerly created for all vregs and then removed as
throwing instructions with undefined locals are encountered. This can
be optimized since rougly one third of vregs is already undefined with
the first throwing instruction.

Change-Id: Ia4e66f19ea03f9a129b4b64d4193d262fff45224
2 files changed