Allow structural redefinition on non-final classes.

This adds support for structurally redefining non-final,
non-finalizable classes. The only restriction is that one cannot
redefine a class at the same time as any of its supertypes, if a
structural redefinition is occurring. The structural redefinition may
not remove any fields or methods, change the superclass or change the
implemented interfaces. Adding new methods or fields, both static or
non-static, public, private, protected, or package-private, is
supported.

Test: ./test.py --host
Bug: 134162467
Bug: 144168550
Change-Id: I32e9e854b3e56270170b10e8f5aba9de8f6bfdfa
47 files changed