Add more standard structural redefinition entrypoints

Add structural redefinition extension function and event that mirror
the 'RedefineClasses' function and 'ClassFileLoadHook' event. The new
extension function is called
'com.android.art.class.structurally_redefine_classes' and the new
extension event is called
'com.android.art.class.structural_dex_file_load_hook'.

These extensions are the preferred way to use structural redefinition.
Like the standard 'RedefineClasses' multiple classes may be redefined
at a time.

The structural_dex_file_load_hook is triggered prior to the
can_retransform_classes ClassFileLoadHook. It is triggered on all
classes, even ones that cannot be structurally changed by
class-loading, class redefinition or by calling the RetransformClasses
function.

Calling 'structurally_redefine_classes' with new definitions that do
not require structural changes will fall back to non-structural
redefinition.

Test: ./test.py --host
Bug: 134162467
Change-Id: If4810930470c5c6509cf6db779910006e114b39f
33 files changed