fix vacuum bug on nop'ing an if whose body has brs that cause type changes when removed

Author: kripken

src/passes/Vacuum.cpp

@@ -225,6 +225,7 @@ struct Vacuum : public WalkerPass<PostWalker<Vacuum>> {
           child = curr->ifFalse;
           typeUpdater.noteRecursiveRemoval(curr->ifTrue);
         } else {
+          typeUpdater.noteRecursiveRemoval(curr);
           ExpressionManipulator::nop(curr);
           return;
         }

test/passes/vacuum.txt

@@ -301,4 +301,8 @@
    )
   )
  )
+ (func $nop-if-type-changes (type $0)
+  (local $0 i32)
+  (nop)
+ )
 )

test/passes/vacuum.wast

@@ -637,4 +637,27 @@
     (i32.const 1579493952)
    )
   )
+  (func $nop-if-type-changes (type $0)
+   (local $0 i32)
+   (block $label$0
+    (if
+     (i32.eqz
+      (get_local $0)
+     )
+     (block $label$1
+      (block
+       (if ;; we nop this if, which has a type change for block $label$1, no more brs to it
+        (i32.const 0)
+        (br_if $label$1
+          (i32.const 1717966400)
+        )
+       )
+       (drop
+        (br $label$0)
+       )
+      )
+     )
+    )
+   )
+  )
 )