optimize logical and/or, initial null checking in flows

tests/compiler/std/static-array.untouched.wat

@@ -1305,7 +1305,7 @@
    i32.load
    i32.le_u
   else   
-   local.get $2
+   i32.const 0
   end
   if
    loop $continue|0
@@ -1330,14 +1330,12 @@
  )
  (func $~lib/runtime/runtime.flags (; 32 ;) (type $FUNCSIG$ii) (param $0 i32) (result i32)
   (local $1 i32)
-  (local $2 i32)
   global.get $~lib/runtime/RTTI_BASE
   local.set $1
   local.get $0
   i32.eqz
-  local.tee $2
   if (result i32)
-   local.get $2
+   i32.const 1
   else   
    local.get $0
    local.get $1