8236073: G1: Use SoftMaxHeapSize to guide GC heuristics

@@ -134,10 +134,12 @@
   // Memory left to use/expand in this virtual space.
   size_t uncommitted_size() const;
 
   void commit_and_set_special();
 
+  bool is_special() const { return _special; }
+
   bool contains(const void* p) const;
 
   MemRegion reserved() {
     MemRegion x((HeapWord*)_low_boundary, reserved_size() / HeapWordSize);
     return x;