Report NON_VARARG_SPREAD on missed cases

^KT-48162 Fixed

compiler/testData/diagnostics/tests/varargs/kt48162.kt

@@ -0,0 +1,22 @@
+// !DIAGNOSTICS: -UNCHECKED_CAST
+
+fun <T> Collection<T>.toArray(): Array<T> = this as Array<T>
+fun Collection<String>.toArray2(): Array<String> = this as Array<String>
+fun <T> toArray3(x: Collection<T>): Array<T> = x as Array<T>
+
+class Foo<T> {
+    operator fun plus(x: Foo<T>): Array<T> {
+        return this + x
+    }
+}
+
+fun use(arg: Array<String>, s: Collection<String>, x: Foo<String>) {
+    arr(<!NON_VARARG_SPREAD_ERROR!>*<!>arg)
+    arr(<!NON_VARARG_SPREAD_WARNING!>*<!>s.toArray())
+    arr(<!NON_VARARG_SPREAD_ERROR!>*<!>s.toArray2())
+    arr(<!NON_VARARG_SPREAD_WARNING!>*<!>toArray3(s))
+    arr(<!NON_VARARG_SPREAD_ERROR!>*<!>x + x)
+    arr(<!NON_VARARG_SPREAD_ERROR!>*<!>(x + x))
+}
+
+fun arr(x: Array<String>) {}