KT-2310: js: !! translated incorrectly (syntax ok, but logic not).

#KT-2310 Fixed

js/js.translator/testFiles/expression/misc/cases/exclExclResultIsComputedOnce.kt

@@ -0,0 +1,12 @@
+package foo
+
+var c = 0
+val a: Int?
+  get() {
+      c++
+      return 2
+  }
+
+fun box() : Boolean {
+  return c == 0 && (a!! + 3) == 5 && c == 1
+}