math:tan: Generate unit testing data on [0, 2pi]

[mansourmoufid]

Hi,

I noticed the unit testing data (gold) for the tangent function seems to be bound to [-1, 1] but it should be bound to [0, 2pi]. (This was mentioned in #166.) So I generated new data.

Ironically, my tangent implementation had a couple bugs, but produced good results with the bad data...

I generated the new data in Python:

>>> import math
>>> n = 100
>>> x = [2.0 * math.pi / n * i for i in range(n)]
>>> data = [(a, 0.0, 0.0, math.tan(a)) for a in x]
>>> for (a, b, c, d) in data:
...     print("{:.6f},{:.6f},{:.6f},{:.6f}".format(a, b, c, d))

I removed two lines for input close to a multiple of pi/2 since they produce garbage (+/- infinity).

This new data helped me fix two bugs.

[mateunho]

Please use #defines from pal_math.h, eg. M_PI_4

[mansourmoufid]

On platforms with math.h, M_PI_4 and other constants are defined with type double. When you mix single and double floating-point arithmetic the compiler produces much slower code.