RFE: COMPILE_METHOD_LOAD event to specify PC to bci mapping

The current JVMPI specifies COMPILE_METOD_LOAD to provide PC to source
line mapping. The actual implementation rarely generates such a mapping and
even when it does, its quality is quite low. It is believed that the dynamic
compiler should rather provide PC to byte-code index mapping and leave the rest
to profiling tools, which should map available information to source lines
using line number information from class files.