refactor(turbo-tasks-memory): Minor cleanup of code in turbo-tasks-me… #10787

Job	Run time
deploy-target	10s
build	2m 13s
build-wasm (web)	22s
build-wasm (nodejs)	22s
stable - aarch64-apple-darwin - node@16	1m 56s
stable - x86_64-pc-windows-msvc - node@16	1m 41s
stable - x86_64-unknown-linux-gnu - node@16	45s
Deploy examples	0s
Deploy preview tarball	2m 7s
Potentially publish release	0s
Upload Turbopack Bytesize metrics to Datadog	0s
Release Stats	0s
	9m 36s

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