Add MultiFileHighlightingTest which checks that other files are not parsed during highlighting

idea/testData/multiFileHighlighting/dependencies/util.kt

@@ -0,0 +1,49 @@
+public package util
+
+trait T {
+    fun f()
+}
+
+trait T2 {
+    fun g() {
+    }
+}
+
+suppress("UNRESOLVED_REFERENCE")
+class Invalid: I
+
+class A(val i: Int)
+
+suppress("FINAL_SUPERTYPE")
+class B: A(1) {
+}
+
+open class C(val s: String, i: Int): A(i), T {
+    override fun f() {}
+}
+
+fun topLevelFun(u: A): A {
+    return A(u.i)
+}
+
+val topLevelVal: A = C("", 0)
+var topLevelVar: A = B()
+
+object topLevelObject: T {
+    override fun f() {
+
+    }
+
+    fun g() {
+    }
+}
+
+fun funWithUnspecifiedType() = 3
+
+fun funWithVararg(vararg i: Int): IntArray {
+    return i
+}
+
+fun <T, G> funWithWhere(a: G, b: T) where T: Collection<G> {
+
+}