Add log and log2 benchmark

Similar to exp/exp2, this patch add two benchmarks for log and log2:
one which measures thoughput and one which measures latency.

The input data is based on logf/log2f one (reduced trace based on 2.8
billion samples extracted from specpu2017 521.wrf_r benchmark).

Test: ran 32-bit and 64-bit x86 tests on host

Change-Id: I51a9e2960e45d5619585e685eaa7634cc7be901b