[cmake] re-configure loop

sometimes, qt-creator ends up in "cmake configure loop": cmake will be executed over and over again until i restart qtc (sometimes it leaves the loop on its own, though).

observations:

• it never seems to happen once a project has been configured correctly and cmake is executed successfully
• adding a new cmake configuration or importing a new cmake project sometimes triggers this loop
• if the cmake build folder is not configured correctly (e.g. due to a cmake syntax error) and the next cmake configure is executed, it sometimes triggers the loop

when this happens, the terminal shows some soft assertions:

SOFT ASSERT: "d->m_isParsing" in file /home/qt/work/build/qt-creator/src/plugins/projectexplorer/project.cpp, line 529

SOFT ASSERT: "!project()->isParsing()" in file /home/qt/work/build/qt-creator/src/plugins/projectexplorer/buildsystem.cpp, line 80

SOFT ASSERT: "!d->m_isParsing" in file /home/qt/work/build/qt-creator/src/plugins/projectexplorer/project.cpp, line 518

SOFT ASSERT: "d->m_isParsing" in file /home/qt/work/build/qt-creator/src/plugins/projectexplorer/project.cpp, line 529

i've seen this with different cmake version on macos, win32 and linux. typically restarting qtcreator solves this issue