Update emitter statistics

Update emitter statistics

1. Move BasicBlock static statistics output to block.cpp,
and update it to match the current BasicBlock declaration.
2. Add counts for each instrDesc type that is used.
3. Dump instrDesc type sizes.
4. Dump IG "static" buffer sizes.
5. Dump how many of each instrDesc can fit in the "static" IG.
6. Dump the maximum prolog instrDesc count and prolog IG size.
7. Fix and enable the "common small constants" output.