[REG 5.11->5.12] macOS: QOpenGLContext::makeCurrent() hangs when called in non-main thread

Steps to reproduce:
1. Create QWindow with OpenGLSurface
2. Create QOpenGLContext
3. Move context to worker thread
4. Call QOpenGLContext::makeCurrent() from worker thread

Expected result:
All works fine

Current result:
Program hangs

Simple example: QTBUG-76148.zip
The bug is stable reproduced only on macOS 10.14.x.

Possible workaround:
Works correctly when call makeCurrent() before moving context to worker thread:

	m_context->makeCurrent(surface);
	m_context->doneCurrent();

	m_context->moveToThread(...);