RFR: 8222148: [lworld] Value type check(guard) causes not working lock coarsening optimization.

[Roland Westrelin]

http://cr.openjdk.java.net/~roland/8222148/webrev.00/

This moves the test for a monitorenter on a value right before we enter
the slow path call so it's mostly free. The change to runtime/init.cpp
fixes printing of stubs generated by generate_return_value_stub() so
it's possible to run benchmarks with -prof perfasm.

Roland.