One of the cached Lambda forms in MethodTypeForm is LF_INTERPRET, the interpreter entrypoint for lambda forms that have the given erased method type form. (Can't use basic types because there is primitive-specific boxing and unboxing)

This lambda form is only created and used in LambdaForm::prepare, and only its vmentry is ever used. We can change the cache in MethodTypeForm to be a SoftReference on a MemberName. Then, we can also remove LambdaForm::createBlankForType.