Use `fmul` in `log10` intrinsic #225

Job	Run time
Lint	6m 6s
cargo-deny	1m 21s
Test (ubuntu-20.04, x86_64-unknown-linux-gnu)	15m 55s
Test (windows-2022, x86_64-pc-windows-msvc)	28m 40s
Test (macOS-latest, x86_64-apple-darwin)	16m 0s
Test (ubuntu-20.04, aarch64-linux-android, x86_64-unknown-linux-gnu)	8m 24s
test_success	1s
	1h 16m 27s

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