Add ProfilerExcimer

Add ProfilerExcimer

Add a Profiler subclass for the new excimer extension. Since it does not
provide function counts, it's a little bit awkward to return it in the
format required by getFunctionStats(), but getOutput() works quite well.

Fix totally broken ProfilerOutputDb, the first parameter to the
onTransactionCommitOrIdle callback is not a Database. It is in the
second parameter, but most callers do not use it.

Change-Id: Icb20f3a5b0b09ff2905f1711f3681c398aa026e2
Depends-On: I6a9ccf5a12ef998e029033adf08af95c42fb7f8e