Do not send clipboard message to application under debugger.

Fix Qt Creator hang when copying a stack trace from an
application showing a runtime assert.

Change-Id: I874bd48643ebce1a3551644dc850cb7cf5869522
Reviewed-by: Kai Koehne <kai.koehne@digia.com>
Reviewed-by: Joerg Bornemann <joerg.bornemann@digia.com>
(cherry picked from qtbase/333817b9cf1304cca7c1dbd45880115cd128f60e)
execute some loops even in cumulative mode

we execute foreach loops now. this is (mostly) safe nowadays, because
a previous change added precautions against exponential value list
growth, so it's unlikely that two nested loops would keep the cpu busy
for a day as before.

we continue to exclude forever loops and loops with excessive integer
counts.

Task-number: QTBUG-8550
Change-Id: Iaa116086986cc7fd5023834753f791dd205102e5
Reviewed-by: Daniel Teske <daniel.teske@digia.com>
Reviewed-by: Oswald Buddenhagen <oswald.buddenhagen@digia.com>
(cherry picked from qttools/dd4d594c787a62fa8aa12695c5d115c71b59bacd)