[lworld] Syntax and other mechanical changes in langtools tests for JDK-8237072

JDK-8237072 adds supports for the new syntax notation of V.ref and V.val to refer to the reference projection of a value type V and its value projection. This change also has class file implications where the descriptor/signature encodings will now start mentioning $ref in the class pool entries.

This ticket is to make the changes necessary for the langtools tests in valhalla to co-evolve with JDK-8237072.

I am including those tests that involve only mechanical and so "uninteresting changes" here. If a test meaningfully changes, it will be included in JDK-8237072 itself.

This is to simplify the review process so that the changeset for JDK-8237072 is not cluttered with all the mechanical changes.