Do not create a HBoundType when the instruction is non-null.

We don't need to refine the type after a null check, if the
instruction is known non null or null. As a side effect, this
avoids replacing HLoadClass instructions with HBoundType instructions.

bug:22116987

(cherry picked from commit 3abd437507f8ba30a238a52c273c9944dcb9d5a1)

Change-Id: I5e56de293554534195ade9770b7d1e4b078d685b
3 files changed