wasm: threaded app deadlock or crash

Anything with thread use in 5.14 either deadlocks or crashes on webassembly.

Using the mandlebrot app, the image never appears.

When I try blockingfortuneclient and new threaded socekts for wasm patch (which worked before), the effect is more dramatic:

QMessageLogger::fatal(char const*, ...) const [__ZNK14QMessageLogger5fatalEPKcz]@http://192.168.1.106:6931/blockingfortuneclient.wasm:wasm-function[19314]:0x5a61ee
QOpenGLContext::makeCurrent(QSurface*) [__ZN14QOpenGLContext11makeCurrentEP8QSurface]@http://192.168.1.106:6931/blockingfortuneclient.wasm:wasm-function[10362]:0x3b1b4f
QWasmCompositor::frame() [__ZN15QWasmCompositor5frameEv]@http://192.168.1.106:6931/blockingfortuneclient.wasm:wasm-function[789]:0x21525
QWasmCompositor::event(QEvent*) [__ZN15QWasmCompositor5eventEP6QEvent]@http://192.168.1.106:6931/blockingfortuneclient.wasm:wasm-function[788]:0x213f1
QApplicationPrivate::notify_helper(QObject*, QEvent*) [__ZN19QApplicationPrivate13notify_helperEP7QObjectP6QEvent]@http://192.168.1.106:6931/blockingfortuneclient.wasm:wasm-function[2168]:0xf31c9
QApplication::notify(QObject*, QEvent*) [__ZN12QApplication6notifyEP7QObjectP6QEvent]@http://192.168.1.106:6931/blockingfortuneclient.wasm:wasm-function[2166]:0xf2f1a
QCoreApplication::notifyInternal2(QObject*, QEvent*) [__ZN16QCoreApplication15notifyInternal2EP7QObjectP6QEvent]@http://192.168.1.106:6931/blockingfortuneclient.wasm:wasm-function[23214]:0x676575
QCoreApplication::sendEvent(QObject*, QEvent*) [__ZN16QCoreApplication9sendEventEP7QObjectP6QEvent]@http://192.168.1.106:6931/blockingfortuneclient.wasm:wasm-function[23225]:0x676bb6
QCoreApplicationPrivate::sendPostedEvents(QObject*, int, QThreadData*)