Benchmark test for bpf map operation

Add some simple tests for benchmarking the performance of eBPF map
operations such as insert new entry, update a existing entry and
delete a entry from the map. A typical result is like:
------------------------------------------------------------------------
Benchmark                                 Time           CPU Iterations
------------------------------------------------------------------------
BpfBenchMark/MapUpdateEntry/1           626 ns        623 ns    1137521
BpfBenchMark/MapWriteNewEntry/1        1145 ns       1140 ns     607525
BpfBenchMark/MapDeleteAddEntry/1       1111 ns       1105 ns     633355

Bug: 112068616
Test: ./bpf_benchmark
Change-Id: I3c325496041be1c4b21f8fdd011d1219f8de1ed1
2 files changed