Native: fix objc_direct tests on platforms with 32-bit NSUInteger

On some platforms, `NSUInteger` is 32-bit, while the objc_direct tests
expected it to be represented as `ULong`. So the tests failed on those
platforms.
Fix the tests by replacing `NSUInteger` with `uint64_t`.

kotlin-native/backend.native/tests/interop/objc/direct/direct.h

@@ -6,21 +6,21 @@ __attribute__((objc_runtime_name("CC")))
 __attribute__((swift_name("CC")))
 @interface CallingConventions : NSObject
 
-+ (NSUInteger)regular:(NSUInteger)arg;
-- (NSUInteger)regular:(NSUInteger)arg;
++ (uint64_t)regular:(uint64_t)arg;
+- (uint64_t)regular:(uint64_t)arg;
 
-+ (NSUInteger)direct:(NSUInteger)arg __attribute__((objc_direct));
-- (NSUInteger)direct:(NSUInteger)arg __attribute__((objc_direct));
++ (uint64_t)direct:(uint64_t)arg __attribute__((objc_direct));
+- (uint64_t)direct:(uint64_t)arg __attribute__((objc_direct));
 
 @end
 
 @interface CallingConventions(Ext)
 
-+ (NSUInteger)regularExt:(NSUInteger)arg;
-- (NSUInteger)regularExt:(NSUInteger)arg;
++ (uint64_t)regularExt:(uint64_t)arg;
+- (uint64_t)regularExt:(uint64_t)arg;
 
-+ (NSUInteger)directExt:(NSUInteger)arg __attribute__((objc_direct));
-- (NSUInteger)directExt:(NSUInteger)arg __attribute__((objc_direct));
++ (uint64_t)directExt:(uint64_t)arg __attribute__((objc_direct));
+- (uint64_t)directExt:(uint64_t)arg __attribute__((objc_direct));
 
 @end
 

kotlin-native/backend.native/tests/interop/objc/direct/direct.m

@@ -1,6 +1,6 @@
 #import "direct.h"
 
-#define TEST_METHOD_IMPL(NAME) (NSUInteger)NAME:(NSUInteger)arg { return arg; }
+#define TEST_METHOD_IMPL(NAME) (uint64_t)NAME:(uint64_t)arg { return arg; }
 
 @implementation CallingConventions : NSObject