qmltest test fails on Mac OS X

qtdeclarative/tests/auto/qmltest/qmltest.pro is makred as an insignificant_test, meaning that test results are discarded and the tests does not help CI to block regressions.

EXamining recent CI logs shows that there are two tests called qmltest (search the test log for "Testing qmltest") – one which passes consistently with 11 passes and 1 skip, and another that occasionally fails with 177 passes and 1 fail.

These two tests should be disambiguated by changing one of the names, and the unstable failure should be investigated.