The C2 compiler has several frequency constant thresholds used by the register allocator
and other parts of the backend.

Bug 6417150 marked each of these with a BLOCK_FREQUENCY macro which normalizes them relative to an expected invocation count of 1 (previously 1500). This RFE should re-tune the values and remove the scaling.

This mostly a cleanup task, so no negative impact on performance is expected. However, the re-tuning may provide a window for some improvement.