Revert "Move runtime/ to ClassAccessor"

Seems to cause 'atest CtsInlineMockingTestCases' and other tests
to fail due to sending agents dex files with hiddenapi flags still
present.

This reverts commit 2649ecf6.

Reason for revert: Seems to be causing sysui test failures, maybe

Bug: 77709234
Bug: 79758018
Bug: 91962648

Test: Tree-Hugger

Change-Id: I2cab5d0d58808dd8beb38400d2811307f26e1021