Finally implement Location::kNoOutputOverlap.

The [i, i + 1) interval scheme we chose for representing
lifetime positions is not optimal for doing this optimization.
It however doesn't prevent recognizing a non-split interval
during the TryAllocateFreeReg phase, and try to re-use
its inputs' registers.

Change-Id: I80a2823b0048d3310becfc5f5fb7b1230dfd8201