IR: don't attempt to move defaults to actual in another module

May happen when a function in an `expect` class is aliased through an
`actual typealias`; the matching declaration is filtered out in
`ExpectedActualResolver.findActualForExpected` as it has no source.

compiler/testData/compileKotlinAgainstKotlin/expectClassActualTypeAlias.kt

@@ -0,0 +1,12 @@
+// !LANGUAGE: +MultiPlatformProjects
+// FILE: impl.kt
+class A(val result: String = "OK")
+
+// FILE: multiplatform.kt
+expect class B(result: String = "FAIL")
+
+actual typealias B = A
+
+fun box(): String {
+    return B().result
+}