use registerize only when not keeping debug, and also use it when closure is disabled, not just ASM_JS mode (which is just one case where closure is disabled)

emcc

@@ -1231,8 +1231,9 @@ try:
     if DEBUG: print >> sys.stderr, 'emcc: running closure'
     final = shared.Building.closure_compiler(final)
     if DEBUG: save_intermediate('closure')
-  elif shared.Settings.ASM_JS and shared.Settings.RELOOP:
-    js_optimizer_queue += ['registerize'] # we can't use closure in asm, but this does much of the same
+  elif shared.Settings.RELOOP and not closure and not keep_debug:
+    # do this if closure is not enabled (it gives similar speedups), and we do not need to keep debug info around
+    js_optimizer_queue += ['registerize']
 
   if opt_level >= 1:
     if DEBUG: print >> sys.stderr, 'emcc: running post-closure post-opts'