More constant folding
More constant folding

Added constant folding for:
rad, deg, sin, cos, tan, asin, acos, atan, sinh, cosh, tanh,
asinh, acosh, atanh, log, log2, exp, exp2, sqrt, inverstsqrt

Change-Id: Ifc6b089e5981da9a3739d4ed7636953a682ce220
Reviewed-on: https://swiftshader-review.googlesource.com/5200
Tested-by: Alexis Hétu <1c7141772178a7e80858c3db5052b328076f08f4@google.com>
Reviewed-by: Nicolas Capens <0612353e1fcebbfd4b302d9337447ca0cdfa9122@google.com>
Tested-by: Nicolas Capens <0612353e1fcebbfd4b302d9337447ca0cdfa9122@google.com>

bkaradzic/SwiftShader,google/swiftshader,bkaradzic/SwiftShader,bkaradzic/SwiftShader,google/swiftshader,bkaradzic/SwiftShader,bkaradzic/SwiftShader,google/swiftshader