UnitTests: Disable self move warnings

We want to test self move, so we cannot avoid the warning.

Change-Id: Id785690d40cfc5299e65c9f0e69abe6e336ba9ff
Reviewed-by: Vikas Pachdha <vikas.pachdha@qt.io>
Reviewed-by: <github-actions-qt-creator@cristianadam.eu>
Reviewed-by: Tim Jenssen <tim.jenssen@qt.io>

tests/unit/unittest/smallstring-test.cpp

@@ -1535,6 +1535,11 @@ TEST(SmallString, LongPathStringMoveConstuctor)
             "text"));
 }
 
+#if __clang__
+#pragma clang diagnostic push
+#pragma clang diagnostic ignored "-Wself-move"
+#endif
+
 TEST(SmallString, ShortSmallStringMoveConstuctorToSelf)
 {
     SmallString text("text");
@@ -1580,6 +1585,10 @@ TEST(SmallString, LongPathStringMoveConstuctorToSelf)
             "text"));
 }
 
+#if __clang__
+#pragma clang diagnostic pop
+#endif
+
 TEST(SmallString, ShortSmallStringCopyAssignment)
 {
     SmallString text("text");