Try to minimize the use of sqrt() and arctan() calls
when possible. These calls can be relatively expensive
when accumulated within a single frame.
Also repalce the division with shift operation.
since split cubic function is one of the significant hot-spots
in the data processing, we could earn a noticable enhancement.
Tested on single thread local machine:
Lottie: 0.080 -> 0.052s (-0.028s)
Performance: 0.023 -> 0.022 (-0.001s)
Binary: +34
Streamlining computations with floating-point operations in rotation
thereby improving 'thorvg' speed.
Also use the well-optimized posix math functions instead of
custom math.
Test on my local machine.
Lottie: -0.008s (0.073 -> 0.065)
Performance: -0.0013s (0.0154 -> 0.0141)
Binary: -323
