[wasm] qtcreator evaluate defined(Q_OS_WASM) as false

    I downloaded qtcreator-4.11 beta1 and enable the webassembly plugin, now I can write qt-wasm project with qtcreator, it's really helpful.

    The only problem I have encountered is that even if I switch to qt-wasm build kit for my project, the editor will gray my wasm specific code for me. The editor will evaluate defined(Q_OS_WASM) as false and wrongly evaluate defined(Q_OS_LINUX) as true, thus it will show linux specific code as normal.