[LLVM][Timing] Legacy pass-manager timer recycled instance with stale names.

Legacy pass-manager timers are keyed by the pass instance pointer and the map entry outlives the pass, so a pass allocated at a recycled address inherits the previous pass's timer and reports its time under that pass's name. When a recycled instance which has different name can end up having leftover name comes from whichever target ran before. Re-create the timer when the name no longer matches.