[REG 4.10 -> 4.11] Wrong additional code completion proposals

1. Run Creator with enabled built-in code model.
2. Create a new Qt Widgets Application project.
3. In the main function, type "unsig".
   The proposal window will show "unsigned", "Q_COMPILER_UNICODE_STRINGS" and "Q_STDLIB_UNICODE_STRINGS". While the first is obviously correct, the latter two don't seem right to me.

Only "unsigned" should be proposed as code completion. In Creator 4.10, this works correctly.

Found by Squish test tst_CSUP01.