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

^KT-61259

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

@@ -0,0 +1,32 @@
+#import "customString.h"
+
+BOOL customStringDeallocated = NO;
+
+@implementation CustomString {
+    NSString* delegate;
+}
+
+- (instancetype)initWithValue:(int)value {
+    if (self = [super init]) {
+        self->delegate = @(value).description;
+        self.value = value;
+    }
+    return self;
+}
+
+- (unichar)characterAtIndex:(NSUInteger)index {
+    return [self->delegate characterAtIndex:index];
+}
+
+- (NSUInteger)length {
+    return self->delegate.length;
+}
+
+- (id)copyWithZone:(NSZone *)zone {
+    return self;
+}
+
+- (void)dealloc {
+    customStringDeallocated = YES;
+}
+@end