should MonitorUsedDeflationThreshold be experimental or diagnostic

[~coleenp] mentioned this RFE during the JDK-8253064 review:

 src/hotspot/share/runtime/globals.hpp
          "The maximum number of monitors to deflate, unlink and delete " \
          "at one time (minimum is 1024).") \
          range(1024, max_jint) \
                                                                            \
  product(intx, MonitorUsedDeflationThreshold, 90, EXPERIMENTAL, \
          "Percentage of used monitors before triggering deflation (0 is " \
          "off). The check is performed on GuaranteedSafepointInterval " \

Should there still be experimental options after this change?

@dcubed-ojdk

Robbin added MonitorUsedDeflationThreshold as an experimental
option back in JDK10. See the longer reply to David's comment.
I don't plan to change that option with this changeset.