ART: Remove DCHECKs for boolean type

Since bool and int are interchangeable types, checking whether an
input is kPrimBoolean can fail when replaced with 0/1 constant or
a phi. This patch removes the problematic DCHECKs, adds a best-effort
verification into SSAChecker but leaves the phi case empty until a
suitable analysis is implemented.

Change-Id: I31e8daf27dd33d2fd74049b82bed1cb7c240c8c6
9 files changed