Add statsd microbenchmark and fix a crash in LogEvent

+ We should benchmark the core functions in the critical path.
     1. LogEvent parsing
     2. Log matching
     3. Event processing in various metrics
     ....

+ Using microbenchmark, we can quantify the optimization we do in the future.

    ---------------------------------------------------------
    Benchmark                  Time           CPU Iterations
    ---------------------------------------------------------
    BM_LogEventCreation       4772 ns       4705 ns     145738

Test: make -j64 statsd_benchmark

Bug: 72242322

Change-Id: I43aa704ffdc7cd21e02ef9038eff66ca7022dbfb