void enableInterrupts() {
    regionLockHolders.computeIfPresent(Thread.currentThread(), (t, b) -> true);
  }
If a handler thread was made ineligible for interrupt via {{@link #disableInterrupts()}, make
it eligible again. No-op if interrupts are already enabled.
hbase-server/src/main/java/org/apache/hadoop/hbase/regionserver/HRegion.java