[K/N][Tests] Split away cache-dependent part of "multiple" test

^KT-61259

native/native.tests/testData/framework/multiple/multiple.swift

@@ -63,9 +63,11 @@ func testIsolation4() throws {
     try assertTrue(obj1 is First.KotlinBase)
     try assertFalse(obj1 is Second.KotlinBase)
 
-    let obj2: Any = Second.SharedKt.getUnexposedStdlibClassInstance()
-    try assertFalse(obj2 is First.KotlinBase)
-    try assertTrue(obj2 is Second.KotlinBase)
+// KT-34261 The following two commented out asserts fail with static caches, see explanation above
+// They are tested separately in multipleFailsWithCaches.swift
+//    let obj2: Any = Second.SharedKt.getUnexposedStdlibClassInstance()
+//    try assertFalse(obj2 is First.KotlinBase)
+//    try assertTrue(obj2 is Second.KotlinBase)
 }
 
 class MultipleTests : TestProvider {

native/native.tests/testData/framework/multiple/multipleFailsWithCaches.swift

@@ -0,0 +1,38 @@
+/*
+ * Copyright 2010-2024 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license
+ * that can be found in the LICENSE file.
+ */
+
+import First
+import Second
+
+// https://youtrack.jetbrains.com/issue/KT-34261
+// When First and Second are static frameworks with caches, this test fails due to bad cache isolation:
+// Caches included into both frameworks have 'ktypew' globals (with same name, hidden visibility and common linkage)
+// for writable part of this "unexposed stdlib class" TypeInfo.
+// ld ignores hidden visibility and merges common globals, so two independent frameworks happen to share
+// the same global instead of two different globals. Things go wrong at runtime then: this writable TypeInfo part
+// is used to store Obj-C class for this Kotlin class. So after the first object is obtained in Swift, both TypeInfos
+// have its class, and the second object is wrong then.
+func testIsolation4() throws {
+    let obj1: Any = First.SharedKt.getUnexposedStdlibClassInstance()
+    try assertTrue(obj1 is First.KotlinBase)
+    try assertFalse(obj1 is Second.KotlinBase)
+
+// With static caches, after `getUnexposedStdlibClassInstance` invocation above,
+// the following two asserts will fail until KT-34261 will be fixed
+    let obj2: Any = Second.SharedKt.getUnexposedStdlibClassInstance()
+    try assertFalse(obj2 is First.KotlinBase)
+    try assertTrue(obj2 is Second.KotlinBase)
+}
+
+class MultipleFailsWithCachesTests : TestProvider {
+    var tests: [TestCase] = []
+
+    init() {
+        tests = [
+            TestCase(name: "TestIsolation4", method: withAutorelease(testIsolation4)),
+        ]
+        providers.append(self)
+    }
+}