Improve codegen for checkMaxBetweenExclusiveImpl(Node3

$ ninja -C build && nm -C -S build/CMakeFiles/conflict-set-object.dir/ConflictSet.cpp.o | grep 'checkMaxBetweenExclusive(Node3'
...
0000000000000000 0000000000000529 T checkMaxBetweenExclusive(Node3*, int, int, InternalVersionT, ReadContext*)
$ git stash pop
...
$ ninja -C build && nm -C -S build/CMakeFiles/conflict-set-object.dir/ConflictSet.cpp.o | grep 'checkMaxBetweenExclusive(Node3'
...
0000000000000000 0000000000000106 T checkMaxBetweenExclusive(Node3*, int, int, InternalVersionT, ReadContext*)

ConflictSet.cpp

@@ -2307,6 +2307,8 @@ bool checkMaxBetweenExclusiveImpl(Node3 *n, int begin, int end,
   assert(!(begin == -1 && end == 256));
 
   auto *self = static_cast<Node3 *>(n);
+  assume(1 <= self->numChildren);
+  assume(self->numChildren <= 3);
 
   ++begin;