test_runner: add exports option for module mocks #4720

Job	Run time
Build slim tarball	2m 44s
x86_64-linux: with shared libraries	21m 8s
x86_64-darwin: with shared libraries	30m 50s
aarch64-linux: with shared libraries	17m 41s
aarch64-darwin: with shared libraries	19m 29s
	1h 31m 52s

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