Run one worker on main thread #2909

Job	Run time
check-labels / check	2s
build-rti / run (ubuntu-latest)	17s
build-trace-tools / run (ubuntu-latest)	5s
fetch-lf / extract-ref	3s
build-rti / run (macos-latest)	12s
build-trace-tools / run (macos-latest)	9s
build-rti / run (windows-latest)	17s
unit-tests-multi / run (ubuntu-latest)	7s
build-trace-tools / run (windows-latest)	13s
unit-tests-single / run (ubuntu-latest)	24s
unit-tests-multi / run (macos-latest)	11s
unit-tests-single / run (macos-latest)	10s
lf-default-flexpret / flexpret-tests	11m 31s
lf-default-arduino / arduino-tests (ubuntu-latest)	3m 19s
lf-default / regular-tests (ubuntu-latest)	27m 28s
lf-adaptive / regular-tests (ubuntu-latest)	25m 39s
lf-default-arduino / arduino-tests (macos-latest)	4m 4s
lf-default / regular-tests (macos-latest)	24m 57s
lf-adaptive / regular-tests (macos-latest)	25m 52s
lf-default / regular-tests (windows-latest)	1h 30m 22s
lf-default-zephyr / zephyr-tests	42m 28s
lf-adaptive / regular-tests (windows-latest)	1h 32m 18s
lf-gedf-np / regular-tests (ubuntu-latest)	25m 32s
lf-python / regular-tests (ubuntu-latest)	16m 49s
lf-gedf-np / regular-tests (macos-latest)	26m 39s
lf-python / regular-tests (macos-latest)	17m 19s
lf-gedf-np / regular-tests (windows-latest)	1h 35m 23s
lf-python / regular-tests (windows-latest)	1h 7m 27s
	9h 59m 17s

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