QtSystems: push down qt.tests.insignificant

So that we can disable qt.tests.insignificant on each project
as soon as it is confirmed as passing.

Change-Id: If9fedfb96f1f08e6c0ed2eff03e0a8169d62fe29
Reviewed-by: Tony Sarajärvi <tony.sarajarvi@digia.com>
Remove qt.tests.insignificant for wince70embedded-armv4i-msvc2008_Windows_7

We don't run tests for wince70embedded-armv4i-msvc2008_Windows_7 so all
these properties are unused.

Change-Id: Icb686e29461150abd37116336773379be0096983
Reviewed-by: Tony Sarajärvi <tony.sarajarvi@digia.com>