test_runner: align MockTimers timeout API #5643

Job	Run time
Build slim tarball	2m 32s
aarch64-linux: with shared libraries	19m 25s
aarch64-darwin: with shared libraries	20m 17s
x86_64-linux: with shared libraries	24m 17s
x86_64-darwin: with shared libraries	27m 32s
	1h 34m 3s

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