The .clang-format file is based on the one in ECM except the following
style options:
- AlwaysBreakBeforeMultilineStrings
- BinPackArguments
- BinPackParameters
- ColumnLimit
- BreakBeforeBraces
- KeepEmptyLinesAtTheStartOfBlocks
The output management test checks the implementation of output
management capabilities in the virtual backend, which is not helpful.
This change replaces it with a more useful test that verifies how
windows are placed after an output change.