identity tests on odd numbers

[yasahi-hpc]

In this PR, I have added tests of 1D FFT over odd numbers. It worked correctly.

const int maxlen     = 32;
for (int i = 1; i < maxlen; i++) {
  ComplexView1DType a("a", i), _a("_a", i), a_ref("a_ref", i);
  ComplexView1DType out("out", i), outr("outr", i / 2 + 1);
  RealView1DType ar("ar", i), _ar("_ar", i), ar_ref("ar_ref", i);

  KokkosFFT::fft(execution_space(), a, out);
  KokkosFFT::ifft(execution_space(), out, _a);

  KokkosFFT::rfft(execution_space(), ar, outr);
  KokkosFFT::irfft(execution_space(), outr, _ar);

  EXPECT_TRUE(allclose(_a, a_ref, 1.e-5, atol));
  EXPECT_TRUE(allclose(_ar, ar_ref, 1.e-5, atol));
}