Make classes of LOS objects non-movable.

When using Generational Concurrent Copying (CC) collection and no boot
image, there is an unlikely case where the class of an object
allocated the Large-Object Space (LOS) might be moved by a
sticky-bit (minor) collection, potentially creating a stale reference
in the `klass_` field of this large object. To prevent this situation,
make all the classes of objects eligible to allocations in the
LOS (large strings and primitive arrays) non-movable when running
without a boot image.

This is not an issue when running with a boot image, as these classes
are in an image space, which is immune.

Also disable run-test 669-moveable-string-class-equals, as this test
expects the String class to be movable when running without a boot
image.

Test: art/test/testrunner/testrunner.py --no-image
Bug: 67628039
Bug: 12687968
Bug: 68181300
Change-Id: Iefce8e13b4d6df96c31d77b7e53b4ba79b5e641c