[FIR] Update backend tests with actual/expect in same module

- The fix for KT-55570 caused some backend tests to fail, because errors
  are now correctly reported for simple classes and actual/expect in
  the same module is not supported in FIR. See KT-55177.
- The commit also adds separate tests for K2. Unfortunately, these have
  to be disabled for K1 because K1 then reports "expect without actual"
  errors.

compiler/testData/codegen/box/compileKotlinAgainstKotlin/expectClassActualTypeAlias.kt

@@ -1,5 +1,8 @@
 // IGNORE_BACKEND: NATIVE
 // !LANGUAGE: +MultiPlatformProjects
+// IGNORE_BACKEND_K2: JVM_IR, JS_IR, NATIVE
+// FIR status: In FIR, declaring the same `expect` and `actual` classes in one compiler module is not possible (see KT-55177).
+
 // MODULE: lib
 // FILE: impl.kt
 class A(val result: String = "OK")

compiler/testData/codegen/box/compileKotlinAgainstKotlin/expectClassActualTypeAlias2.kt

@@ -0,0 +1,20 @@
+// IGNORE_BACKEND: NATIVE
+// !LANGUAGE: +MultiPlatformProjects
+// IGNORE_BACKEND_K1: ANY
+// IGNORE_BACKEND_MULTI_MODULE: ANY
+
+// MODULE: lib1
+// FILE: impl.kt
+class A(val result: String = "OK")
+
+// MODULE: lib2
+// FILE: B.kt
+expect class B(result: String = "FAIL")
+
+// MODULE: main(lib1)()(lib2)
+// FILE: multiplatform.kt
+actual typealias B = A
+
+fun box(): String {
+    return B().result
+}