Remove TreeShims mechanism.

[mbien]

The class is mostly empty at this point and was copied around using an annotation processor.

TreeShims.java was copied to:

./java/java.completion/build/classes-generated/org/netbeans/modules/java/completion/impl
./java/java.editor.base/build/classes-generated/org/netbeans/modules/java/editor/base/semantic
./java/java.editor/build/classes-generated/org/netbeans/modules/editor/java
./java/java.hints/build/classes-generated/org/netbeans/modules/java/hints

[lahodaj]

Looks good to me.

At some point, we should try to get rid of the reflection in java/java.hints/src/org/netbeans/modules/java/hints/jdk/ConvertToSwitchPatternInstanceOf.java, but the proposed state is not conceptually worse than the existing state, so no problem with the proposed state.

[mbien]

thanks for the review! I did look at the reflection snippet at first but didn't want to change too much here (I also don't have much experience with the javac API), the code is copied from the TreeShims class almost unmodified.