code inside QBENCHMARK_ONCE macro executed twice

STEPS LEADING TO PROBLEM:
Check e.g. the following test case: http://meego.gitorious.org/meegotouch/libmeegotouch/blobs/master/benchmarks/pt_mapplication/pt_mapplication.cpp#line40
Here we use QBENCHMARK_ONCE to measure the time to construct an MApplication object.

EXPECTED OUTCOME:
The code in the QBENCHMARK_ONCE macro is really executed just once. We can use QBENCHMARK_ONCE to measure operations which initialize static data.

ACTUAL OUTCOME:
The code in the macro is executed once and then a second time to do the actual measurement.
If the current behavior is really the expected one at least the documentation should mention this.

Maemo6 bug nr: #181889