cmocka: Remove legacy trigonometry suite

All nine CMock trigonometry tests have been ported to Ztest in
test/ztest/unit/math/basic/trigonometry. Remove the now-redundant CMock
suite.

Changes:
 - Delete test/cmocka/src/math/trig/ and all its test files:
     acos_16b_fixed.c, acos_32b_fixed.c
     asin_16b_fixed.c, asin_32b_fixed.c
     cos_16b_fixed.c,  cos_32b_fixed.c
     sin_16b_fixed.c,  sin_32b_fixed.c
     lut_sin_16b_fixed.c
 - Remove the trig subdirectory entry from
     test/cmocka/src/math/CMakeLists.txt
 - Move test/cmocka/include/trig_tables.h to the ztest trigonometry
   directory as a git rename, so the full file history is preserved
   and the ztest suite owns it going forward

Coverage analysis (native_sim, Twister vs. unit_test_defconfig):

CMock stats for trig.c:
 - lines:    92.9 % (92/99)
 - funcs:    75.0 % (3/4)
 - branches: 76.5 % (26/34)

Ztest stats for trig.c:
 - lines:    96.6 % (86/89)
 - funcs:   100.0 % (4/4)
 - branches: 89.6 % (43/48)

CMock stats for lut_trig.c:
 - lines:   100.0 % (26/26)
 - funcs:   100.0 % (1/1)
 - branches: 100.0 % (12/12)

Ztest stats for lut_trig.c:
 - lines:   100.0 % (17/17)
 - funcs:   100.0 % (2/2)
 - branches: 100.0 % (4/4)

Notable improvements in the Ztest suite:
 - cmpx_cexp() was never called by CMock (0 calls); Ztest reaches it
   1002 times, raising trig.c function coverage from 75 % to 100 %
 - lut_sin_16b_fixed test now exercises sofm_sine_lookup_16b() in
   addition to sofm_lut_sin_fixed_16b(), covering both functions in
   lut_trig.c vs. only one in CMock

The previous commit that added test/cmocka/include to the ztest include
path is superseded: trig_tables.h now lives alongside the tests that
use it, so no out-of-tree include directory is needed.

Signed-off-by: Tomasz Leman <tomasz.m.leman@intel.com>

Author: tmleman

test/cmocka/src/math/CMakeLists.txt

@@ -1,6 +1,5 @@
 # SPDX-License-Identifier: BSD-3-Clause
 
-add_subdirectory(trig)
 add_subdirectory(arithmetic)
 add_subdirectory(fft)
 add_subdirectory(window)