RFR: 8215560: [lworld] Investigate if method handle calls can be further optimized

[Roland Westrelin]

Thanks for looking at this, Tobias.

> That seems reasonable to me. Please remove the -DVerifyIR=true in the
> test, it's enabled by default.

Really? For some subtests in the method handle test, we still have IR
patterns that are verified. We still want them to be executed, right?

> How can it happen that ret_val->outcnt() != 0 but return_val_keeps_allocations_alive() returns true?

Right. I will change that to an assert.

> Small typo: "return value keeps otherwise" -> "return value keep otherwise"

Right.

> Please close JDK-8220357 as duplicate.

Ok.

Roland.