Instrument execution with start time and end time - Add start time and end time of each execution - Show execution time of leaf in each test Bug: 140677693 Test: manual test Change-Id: Ib2bb30add4f3a22f19562f9b02f6ec7d689af901 Merged-In: Ib2bb30add4f3a22f19562f9b02f6ec7d689af901