opcodes: Add function for compact summary

Depending on the opcode and its parameters, the existing “Summary”
function can give a rater long summary. For displaying the summary in
logs and in the lock monitor, it should be shorter. Hence this new
function is added to just use the opcode ID with common prefixes
replaced (e.g. “INSTANCE_” becomes “I_”). Opcode values are not used.

Signed-off-by: Michael Hanselmann <hansmi@google.com>
Reviewed-by: Iustin Pop <iustin@google.com>