Allow to remove an enum bit (case) twice

[gisostallenberg]

No description provided.

[gisostallenberg]

Removing an enum case twice currently actually adds the bit

[yaroslavche]

If I understand correctly, these should be some strict methods for adding/removing bits that throw exceptions if the bit is not set when removed and if it is set when added. However, in this particular case, we are not interested in whether the bit is set when removing. If it is set, it will be deleted, if not, it will not. In general, it seems to me that there is no change in the behavior of deletion, only the semantics have changed. Need some time, I will review this change in a few days.

I see the test results, you're right. I need to check if BitMask also has this problem, I will do that.

UPD. This problem exists also in BitMask. That fix must be in BitMask. But actually not foreach, but a check if bit is set before perform bitwise operation. Will do that.