fix #H6203 - jumping over water doesn't

Accidentally caused by my grappling hook fix 2 months ago, attempting
to jump over water made hero enter that water and drown (or crawl out).
hurtle_step() was originally intended to be used for recoil while
levitating, but it is used in other situations where not levitating
and behavior for the two circumstances should be different.

This doesn't fix things properly, just gets jumping working again.

include/youprop.h

@@ -227,7 +227,8 @@
      && !BFlying)
 /* May touch surface; does not override any others */
 
-#define Wwalking (u.uprops[WWALKING].extrinsic && !Is_waterlevel(&u.uz))
+#define EWwalking u.uprops[WWALKING].extrinsic
+#define Wwalking (EWwalking && !Is_waterlevel(&u.uz))
 /* Don't get wet, can't go under water; overrides others except levitation */
 /* Wwalking is meaningless on water level */