Fix bad indentation calculation in the console reporter

The problem came from the console reporter trying to provide a
fancy linebreaking (primarily for things like `SCENARIO` or the
BDD macros), so that new lines start with extra indentation if
the text being line broken starts as "{text}: ".

The console reporter did not properly take into account cases
where the ": " part would already be in a later line, in which
case it would ask for non-sensical level of indentation (larger
than single line length).

We fixed this by also enforcing that the special indentation case
only triggers if the ": " is found early enough in the line, so
that we also avoid degenerate cases like this:
```
blablabla: F
           a
           n
           c
           y
           .
           .
           .
```

Fixes #2309

tests/SelfTest/Baselines/compact.sw.approved.txt

@@ -1449,6 +1449,7 @@ Reporters.tests.cpp:<line number>: passed: listingString, ContainsSubstring( "fa
     </SourceInfo>
   </TestCase>
 </MatchingTests>" ( contains: "fake test name" and contains: "fakeTestTag" ) with 1 message: 'Tested reporter: xml'
+Reporters.tests.cpp:<line number>: passed:
 Message.tests.cpp:<line number>: passed: with 1 message: 'this is a success'
 Message.tests.cpp:<line number>: passed:
 BDD.tests.cpp:<line number>: passed: before == 0 for: 0 == 0