[IntervalTree] Initialize find_iterator::Point

There was initially a msan report for use-of-uninitialized value due to
a bug in https://reviews.llvm.org/D138526. find_iterator::Point is
uninitialized for the default constructor of find_iterator, which is
used by IntervalTree::end. This change is not required, but its good
practice to make sure all class members are initialized.

Differential Revision: https://reviews.llvm.org/D149698

llvm/include/llvm/ADT/IntervalTree.h

@@ -463,7 +463,7 @@ class IntervalTree {
     // Current node and index while traversing the intervals that contain
     // the reference point.
     IntervalNode *Node = nullptr;
-    PointType Point;
+    PointType Point = {};
     unsigned Index = 0;
 
     // For the current node, check if we have intervals that contain the