Remove functions calling the deprecated `_MM_SET_FLUSH_ZERO_MODE` #872

Job	Run time
cargo-check-features (stable, cargo hack check --feature-powerset --no-dev-deps --depth 2 --skip ...	6m 50s
cargo-check-features (nightly, cargo hack check --each-feature --no-dev-deps --features nightly -...	2m 32s
	9m 22s

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