C1: fix "assert(has_printable_bci()) failed: _printable_bci should have been set" when using -XX:+PrintCanonicalization

[Roland Westrelin]

> Thanks for the tip! I didn't notice what the old behavior was
> before 6986046.

As I understand it before 6986046, the code would always print bcis with -XX:+PrintCanonicalization except the bcis would sometimes be -99 (when the instruction was not yet linked).

Roland.