8260632: Build failures after JDK-8253353

Reviewed-by: stuefe, thartmann, kvn

Author: shipilev

src/hotspot/share/gc/shenandoah/c2/shenandoahSupport.cpp

@@ -2285,7 +2285,7 @@ void MemoryGraphFixer::collect_memory_nodes() {
   uint last = _phase->C->unique();
 
 #ifdef ASSERT
-  uint8_t max_depth = 0;
+  uint16_t max_depth = 0;
   for (LoopTreeIterator iter(_phase->ltree_root()); !iter.done(); iter.next()) {
     IdealLoopTree* lpt = iter.current();
     max_depth = MAX2(max_depth, lpt->_nest);