[K/N][Tests] Migrate objcSmoke & objcTests tests

^KT-61259

native/native.tests/testData/interop/objc/tests/customString.h

@@ -0,0 +1,16 @@
+#import <Foundation/NSString.h>
+
+@interface CustomString : NSString
+- (instancetype)initWithValue:(int)value;
+@property int value;
+@end
+
+CustomString* _Nonnull createCustomString(int value) {
+    return [[CustomString alloc] initWithValue:value];
+}
+
+int getCustomStringValue(CustomString* str) {
+    return str.value;
+}
+
+extern BOOL customStringDeallocated;