The fix for JDK-8153224 Monitor deflation prolong safepoints
includes several workarounds for invoking the safepoint
based deflation mechanism via a "special deflation request".
These workarounds are necessary for several tests that
expect certain operations, e.g., System.gc() or the whitebox
equivalents, to deflate idle monitors.

In order to remove the safepoint based deflation mechanism,
we have to provide an alternative whitebox APIs for those
tests that "know too much" about how things work.