test_runner: filter execArgv fallback for child tests #8311

Job	Run time
Build slim tarball	1m 6s
aarch64-linux: Cache V8 build	30s
aarch64-darwin: with shared libraries	23m 7s
x86_64-darwin: with shared libraries	35m 50s
x86_64-linux: with shared libraries	26m 59s
aarch64-linux: with shared boringssl-0.20260526.0	23m 34s
aarch64-linux: with shared openssl-3.5.6	23m 48s
aarch64-linux: with shared openssl-1.1.1w	24m 11s
aarch64-linux: with shared openssl-3.6.2	24m 3s
aarch64-linux: with shared openssl-4.0.0	23m 59s
aarch64-linux: with shared openssl-3.0.20	24m 30s
	3h 51m 37s

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