test_runner: simplify code and make it more consistent #1006

Job	Run time
Build slim tarball	1m 38s
aarch64-darwin: with shared libraries	1m 19s
x86_64-darwin: with shared libraries	2m 34s
aarch64-linux: with shared libraries	16s
x86_64-linux: with shared libraries	16s
x86_64-darwin: with shared libraries	1h 1m 0s
aarch64-darwin: with shared libraries	39m 10s
aarch64-linux: with shared libraries	30m 51s
x86_64-linux: with shared libraries	35m 18s
Build slim tarball	1m 38s
	2h 54m 0s

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