COBBTree: Always initialize x4c_hit

Same behavior, but provides deterministic state on construction, which
can make debugging much nicer.

Runtime/Collision/COBBTree.hpp

@@ -45,7 +45,7 @@ public:
     std::unique_ptr<CNode> x40_left;
     std::unique_ptr<CNode> x44_right;
     std::unique_ptr<CLeafData> x48_leaf;
-    bool x4c_hit;
+    bool x4c_hit = false;
 
   public:
     CNode() = default;