Flaky StemControlTest.StemColor

[Swiftb0y]

Unfortunately StemControlTest.StemColor often fails on CI.

The following tests FAILED:
	871 - StemControlTest.StemColor (Failed)

Relevant log output

./src/test/stemcontrolobjecttest.cpp:164: Failure
Expected equality of these values:
  m_pStem1Color->get()
    Which is: -1
  0xfd << 16 | 0x4a << 8 | 0x4a
    Which is: 16599626

./src/test/stemcontrolobjecttest.cpp:165: Failure
Expected equality of these values:
  m_pStem2Color->get()
    Which is: -1
  0xff << 16 | 0xff << 8 | 0x00
    Which is: 16776960

./src/test/stemcontrolobjecttest.cpp:166: Failure
Expected equality of these values:
  m_pStem3Color->get()
    Which is: -1
  0x00 << 16 | 0xe8 << 8 | 0xe8
    Which is: 59624

./src/test/stemcontrolobjecttest.cpp:167: Failure
Expected equality of these values:
  m_pStem4Color->get()
    Which is: -1
  0xad << 16 | 0x65 << 8 | 0xff
    Which is: 11363839

@acolombier could you do me a favor and look into it?

[Swiftb0y]

You may have to manually spin the event loop even more...