Debugger: Re-use flexible upper limit when cutting off string data

A fixed 100 is too inflexible.

Change-Id: I86e996157ea49c14078b3833a5b08dc53d25d1aa
Reviewed-by: hjk <hjk121@nokiamail.com>
Debugger: Fix part of 2.7 regression in QObject dumper

For e.g. QMap<uint, float>, std::stack<int *>, 73 pass, 103 fail.

Change-Id: I14f68ad59d10e9751d09ed6e0f959d2a78d53822
Reviewed-by: hjk <hjk121@nokiamail.com>
Debugger: Don't use tooltips as labels.

They might be too long...

Change-Id: Ie3f09c6befbbd037ada86d22bda765524de9c18c
Reviewed-by: hjk <hjk121@nokiamail.com>