do not use weird initial sizes for DynArray

For some reason this seems to be a bit slower even for powers of 2.

analyzer.ml

@@ -665,8 +665,8 @@ module BasicBlock = struct
 			bb_type = t;
 			bb_pos = p;
 			bb_closed = false;
-			bb_el = DynArray.make 5;
-			bb_phi = DynArray.make 1;
+			bb_el = DynArray.create();
+			bb_phi = DynArray.create();
 			bb_outgoing = [];
 			bb_incoming = [];
 			bb_dominator = bb;