tink-objc: Disable -Wnonnull for tests that test for NULL arguments on purpose.

PiperOrigin-RevId: 191916150
GitOrigin-RevId: 2383d6305d0d4ca73c312c284bb9ea6d1c153e6f

objc/Tests/UnitTests/core/TINKBinaryKeysetReaderTest.mm

@@ -61,6 +61,8 @@ static NSData *gGoodSerializedEncryptedKeyset;
   gGoodSerializedEncryptedKeyset = TINKStringToNSData(encrypted_keyset.SerializeAsString());
 }
 
+#pragma clang diagnostic push
+#pragma clang diagnostic ignored "-Wnonnull"
 - (void)testReaderCreation {
   // Serialized keyset is nil.
   NSError *error = nil;
@@ -83,6 +85,7 @@ static NSData *gGoodSerializedEncryptedKeyset;
   XCTAssertNotNil(reader);
   XCTAssertNil(error);
 }
+#pragma clang diagnostic pop
 
 - (void)testReadFromString {
   // Good std::string.

objc/Tests/UnitTests/core/TINKKeysetHandleTest.mm

@@ -145,12 +145,15 @@ static TINKPBKeyset *gKeyset;
   XCTAssertEqual(error.code, crypto::tink::util::error::INVALID_ARGUMENT);
 }
 
+#pragma clang diagnostic push
+#pragma clang diagnostic ignored "-Wnonnull"
 - (void)testInvalidKeyTemplate {
   NSError *error = nil;
   TINKKeysetHandle *handle = [[TINKKeysetHandle alloc] initWithKeyTemplate:nil error:&error];
   XCTAssertNil(handle);
   XCTAssertEqual(error.code, crypto::tink::util::error::INVALID_ARGUMENT);
 }
+#pragma clang diagnostic pop
 
 - (void)testValidKeyTeamplte {
   // TODO(candrian): Implement this once the C++ method is working.