Quit using weightChildNode for ADDITIONAL_PROXIMITY and SUBSTITUTION.

[Category diff]
+1       0
-1       1
+2       0
-2       0
+3       0
-3       0
+4       1
-4       1
+5       8
-5       7
+6       0
-6       1
+7       1
-7       0

[Weighted category diff]
+1       0
-1       1
+2       0
-2       0
+3       0
-3       0
+4       1
-4       1
+5       8
-5       7
+6       0
-6       1
+7       1
-7       0

Bug: 13756409
Change-Id: I6ac3567545676bbefbee3e87dda54bc083c15fb6