Use `fmul` in `log10` intrinsic #224

Job	Run time
Lint	1m 39s
Test (ubuntu-20.04, x86_64-unknown-linux-gnu)	1m 38s
cargo-deny	1m 31s
Test (windows-2022, x86_64-pc-windows-msvc)	1m 31s
Test (macOS-latest, x86_64-apple-darwin)	1m 41s
Test (ubuntu-20.04, aarch64-linux-android, x86_64-unknown-linux-gnu)	1m 39s
test_success	1s
	9m 40s

Provide feedback