Previously, JUCE_ANDROID_REALTIME_THREAD_AVAILABLE sometimes remained
unset, even though JUCE_USE_ANDROID_OBOE was set to its default value.
This is because in this case, JUCE_USE_ANDROID_OBOE is only defined in
juce_audio_basics.h, so it is not visible when compiling juce_core.cpp.

Requesting a callback when opening an Oboe device is required on some devices to get a FAST stream, so pass a dummy callback object to the temporary stream used when querying the device buffer size in order to get the best available.

Please see the forum post "Re-structuring of JUCE’s low-level Android code" and the BREAKING-CHANGES.txt for more information.