[ObjCType] Add basic implementation of base method, fix tests

KT-65687

native/objcexport-header-generator/testData/headers/privateGenericSuperInterface/!privateGenericSuperInterface.h

@@ -0,0 +1,30 @@
+#import <Foundation/NSArray.h>
+#import <Foundation/NSDictionary.h>
+#import <Foundation/NSError.h>
+#import <Foundation/NSObject.h>
+#import <Foundation/NSSet.h>
+#import <Foundation/NSString.h>
+#import <Foundation/NSValue.h>
+
+NS_ASSUME_NONNULL_BEGIN
+#pragma clang diagnostic push
+#pragma clang diagnostic ignored "-Wunknown-warning-option"
+#pragma clang diagnostic ignored "-Wincompatible-property-type"
+#pragma clang diagnostic ignored "-Wnullability"
+
+#pragma push_macro("_Nullable_result")
+#if !__has_feature(nullability_nullable_result)
+#undef _Nullable_result
+#define _Nullable_result _Nullable
+#endif
+
+__attribute__((objc_subclassing_restricted))
+@interface PublicClass : Base
+- (instancetype)init __attribute__((swift_name("init()"))) __attribute__((objc_designated_initializer));
++ (instancetype)new __attribute__((availability(swift, unavailable, message="use object initializers instead")));
+- (int32_t)foo __attribute__((swift_name("foo()")));
+@end
+
+#pragma pop_macro("_Nullable_result")
+#pragma clang diagnostic pop
+NS_ASSUME_NONNULL_END

native/objcexport-header-generator/testData/headers/privateGenericSuperInterface/Foo.kt

@@ -0,0 +1,7 @@
+private interface PrivateInterface<T> {
+    fun foo(): T
+}
+
+class PublicClass : PrivateInterface<Int> {
+    override fun foo(): Int = error("stub")
+}