dx: Add additional phi overlaps to liveness analysis

For pairs of phi functions within a basic block, mark the source and
result registers as interferring.

Bug: 63722269
Bug: 34992456
Bug: 64098454
Test: dx/tests/run-all-tests
Change-Id: Idb7a488b98bb4ca80aecc892c69d7dc31b8c5681
5 files changed