Consider optimization of Math functions using hand crafted IR and native code

The Math methods sin, cos, tan, asin, acos, atan, atan2, exp, log, sqrt, pow, IEEEremainder, ceil, floor, rint, cbrt, cosh, expml, hypot, log10, log1p, sinh and tanh are implemented by syscalls (calls into C code). They are also marked as @Pure so that we can fold them when they have constant arguments. When this fails a number of these could be implemented using x86 FPU opcodes. This supersedes the old SF RFE 1519980.