Fix PerfLogger for recursive methods

Currently PerfLogger stores its startTimes and endTimes in a Map, where the key is a String variable called method. The method perfLogBegin simply overwrites the values in the Map. This doesn't work for recursive methods, as there are multiple calls to perfLogBegin and they all overwrite the same key in the Map. Ideally, for each method, we should log start time of the first perfLogBegin and end time of the last perfLogEnd calls.

The issue isn't restricted to just strictly recursive methods like doPhase1; we run into the same issue if we try to log BaseSemanticAnalyzer.analyze method and run an explain cbo. The analyze method will get called once for ExplainSemanticAnalyzer and again for CalcitePlanner. The second perfLogBegin call would overwrite the start time and we would get incorrect values.