[C++] Add missing scalar arithmetic function: expm1()

[felipecrv]

Describe the enhancement requested

Add Expm1(exponent) scalar arithmetic function.

Expm1(exponent) is a more accurate way of computing Exp(exponent) - 1.0 for small values of exponent. Implementations are provided by standard C library implementations.

Component(s)

C++

[felipecrv]

Issue resolved by pull request 44904
#44904