Update dead_alloc_elim.sil

Author: Azoy

test/SILOptimizer/dead_alloc_elim.sil

@@ -716,8 +716,8 @@ bb0(%0 : $_ContiguousArrayStorage<Element>):
 sil @dead_zero_init : $@convention(thin) () -> () {
 bb0:
   %0 = alloc_stack $Kl
-  builtin "zeroInitializer"(%0 : $*Kl)
-  dealloc_stack %0
+  %empty = builtin "zeroInitializer"(%0 : $*Kl) : $()
+  dealloc_stack %0 : $*Kl
   %1 = tuple ()
   return %1
 }