test: fix incorrect calculation in test-perf-hooks.js #24

Job	Run time
aarch64-darwin: with shared libraries	30m 28s
aarch64-linux: with shared libraries	24m 29s
x86_64-linux: with shared libraries	28m 11s
x86_64-darwin: with shared libraries	1h 0m 4s
	2h 23m 12s

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