Changed initial guess from a simple x/3 to dividing the exponent by 2.
This makes large or small numbers like 10e10 and 01e-10 converge in a few
loops.
Added a loop counter to ensure that the algorithm breaks out of the loop in
the case that the algorithm doesn't converge (toggling between two
numbers).
Added test cases for sqrt and sqrtf in libc. Tested with a range of numbers
between 10e10 and 10e-10. Verify good accuracy in test case.
Closes: #55962
Signed-off-by: Lawrence King <lawrencek52@gmail.com>