[Wasm] fix tests for className wasm (KT-69621)

Author: alex28sh

core/commonTest/src/kotlinx/serialization/modules/ModuleBuildersTest.kt

@@ -227,8 +227,21 @@ class ModuleBuildersTest {
                 subclass(C2::class)
             }
         }
-        val classNameMsg = if (currentPlatform == Platform.JS || currentPlatform == Platform.WASM) "class Any" else "class kotlin.Any"
-        assertFailsWithMessage<IllegalArgumentException>("Multiple polymorphic serializers in a scope of '$classNameMsg' have the same serial name 'C'") { c1 + c2 }
+        val classNameMsg = if (currentPlatform == Platform.JS) "class Any" else "class kotlin.Any"
+        // In WASM the class name may appear as either "class Any" or "class kotlin.Any" due to changing API
+        if (currentPlatform == Platform.WASM) {
+            val ex = assertFailsWith<IllegalArgumentException> { c1 + c2 }
+            val expected1 = "Multiple polymorphic serializers in a scope of 'class Any' have the same serial name 'C'"
+            val expected2 = "Multiple polymorphic serializers in a scope of 'class kotlin.Any' have the same serial name 'C'"
+            assertTrue(
+                ex.message == expected1 || ex.message == expected2,
+                "Expected exception message to be either:\n'$expected1' or '\n'$expected2' but was: '${ex.message}'"
+            )
+        } else {
+            assertFailsWithMessage<IllegalArgumentException>(
+                "Multiple polymorphic serializers in a scope of '$classNameMsg' have the same serial name 'C'"
+            ) { c1 + c2 }
+        }
         val module = c1 overwriteWith c2
         // C should not be registered at all, C2 should be registered both under "C" and C2::class
         assertEquals(C2.serializer(), module.getPolymorphic(Any::class, serializedClassName = "C"))