JSR 292: reject redefinitions if patched string becomes non-patched and vice versa

Pseudo-strings must remain pseudo-strings and strings remain strings after a class redefinition/retransformation.
We need to put a check in place if the invariant is broken as the pseudo-string patches will be lost in such case.

The suggestion is to reject such redefinitions and return a JVMTI error, something like:
  JVMTI_ERROR_UNSUPPORTED_REDEFINITION_SCHEMA_CHANGED
  JVMTI_ERROR_INTERNAL