private void removeStaleEntries() {
        Object r;
        while ( (r = refQueue.poll()) != null) {
        	MySoftRef e = (MySoftRef)r;
        	values[e.index] = null;
        }
    }
Expunge stale entries from the table.
Ghidra/Features/Base/src/main/java/ghidra/util/table/IntObjectCache.java