As seen in #177570, this code has a bunch of corner cases, does not
handle ANSI codes properly and does not handle unicode at all. That's
enough to fix that we need some tests to make it clear where we're
starting from.
The body of OutputFormattedUsageText is moved into a utility in the
AnsiTerminal.h header and tests added to the existing
AnsiTerminalTest.cpp.
Some results are known to be wrong. Some that cause crashes are
commented out, to be enabled once fixed.