8157453: Convert DependencyContext_test to GTest
Reviewed-by: dholmes, rehn, kzhaldyb

8144024: Octane fails with "memory leak: allocating handle outside HandleMark"
Reviewed-by: kvn

8143408: Crash during InstanceKlass unloading when clearing dependency context
Reviewed-by: kvn

8139595: MethodHandles::remove_dependent_nmethod is not MT safe
Reviewed-by: jrose, coleenp