8010722: assert: failed: heap size is too big for compressed oops

Use conservative assumptions of required alignment for the various garbage collector components into account when determining the maximum heap size that supports compressed oops. Using this conservative value avoids several circular dependencies in the calculation.

Reviewed-by: stefank, dholmes

hotspot/src/share/vm/gc_implementation/g1/g1CollectedHeap.hpp

@@ -1092,6 +1092,9 @@ public:
   // specified by the policy object.
   jint initialize();
 
+  // Return the (conservative) maximum heap alignment for any G1 heap
+  static size_t conservative_max_heap_alignment();
+
   // Initialize weak reference processing.
   virtual void ref_processing_init();