Benchmark cmath functions compared to their "fast math" equivalent

[ohmtech-rdi]

Our future integrations use "fast math" to replace parts of the standard library with a "faster" equivalent.

Sometimes for example, std::sin is replaced with the CMSIS equivalent, but the implementation doesn't seem to be faster than the one in glibc, unless we are looking at the wrong implementation.

To make sure those are relevant, benchmark them:

• The time they take compared to the standard library one
• The ULP they have compared to the standard library one