flvmux.test_audio_caps_change_streamable: Sometimes times out

https://gitlab.freedesktop.org/gstreamer/gst-plugins-base/-/jobs/429855

GST_STATE_IGNORE_ELEMENTS='aasink autoaudiosrc autoaudiosink autovideosrc
 autovideosink cacasink cairotextoverlay gtkglsink gtksink jackaudiosrc
 jackaudiosink osssrc osssink osxaudiosink osxaudiosrc osxvideosrc osxvideosink
 pulsesink pulsesrc pulsemixer v4l2src' GST_PLUGIN_LOADING_WHITELIST='gstreamer:gst-plugins-base:gst-plugins-good@/builds/gstreamer/gst-plugins-base/gst-build/build' GST_PLUGIN_PATH_1_0='/builds/gstreamer/gst-plugins-base/gst-build/build' GST_REGISTRY='/builds/gstreamer/gst-plugins-base/gst-build/build/subprojects/gst-plugins-good/tests/check/elements_flvmux.registry' GST_CHECKS='test_audio_caps_change_streamable' CK_DEFAULT_TIMEOUT='20' GST_PLUGIN_SYSTEM_PATH_1_0='' /builds/gstreamer/gst-plugins-base/gst-build/build/subprojects/gst-plugins-good/tests/check/elements_flvmux

elements_flvmux output

Running suite(s): flvmux
0%: Checks: 1, Failures: 0, Errors: 1
../subprojects/gst-plugins-good/tests/check/elements/flvmux.c:733:E:general:test_audio_caps_change_streamable:0: (after this point) Test timeout expired
Check suite flvmux ran in 20.001s (tests failed: 1)