[SYCL] Fix edge cases in ctanh and cexp

[jzc]

Due to formatting, the test case diff is a bit hard to see. Here is an overview of the new tests cases added and their old behavior:

ctanh(-inf + nan*i) == -1 + 0*i (previously was 1 + 0*i) ctanh(-inf + nan*i) == -1 + 0*i (previously was 1 + 0*i) ctanh(-inf + nan*i) == -1 + 0*i (previously was 1 + 0*i) cexp(1e6 + 0*i) == inf + 0*i (previously was inf + nan*i) cexp(1e6 + 0.1*i) == inf + inf*i (old behavior, just adding more coverage) cexp(1e6 + -0.*i) == inf + -inf*i (old behavior, just adding more coverage)