Use pre-allocated Throwables from the boot image.

The pre-allocated OOMEs and NoClassDefFoundError were stored
in the boot image but they were not used, we instead used to
allocate and use new objects. This change adds references to
the image roots, so that these Throwables can be used when
starting the runtime using the boot image.

Test: m test-art-host-gtest
Test: testrunner.py --host --optimizing
Bug: 77947463
Change-Id: I2079344dee61242bf0bef5c32770c33ac8a6b7a4