cmocka: Remove normalize int32 tests

This patch removes tests that have been successfully converted to the
new framework (from cmock to ztest).

Code coverage testing did not reveal any regression.

CMock stats for number.c
- lines: 80.4 % (45/56)
- funcs: 83.3 % (5/6)
- branches: 78.1 % (25/32)

Ztest stats for number.c
- lines: 83.6 % (46/55)
- funcs: 83.3 % (5/6)
- branches: 78.9 % (30/38)

These were the last tests from this group and together with them I'm
removing the remaining references in the build system.

Additionally, information about the source of the original code and its
author has been added to the new version of tests.

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(numbers)
 add_subdirectory(trig)
 add_subdirectory(arithmetic)
 add_subdirectory(fft)

test/cmocka/src/math/numbers/CMakeLists.txt

@@ -6,6 +6,8 @@
 // generative artificial intelligence solutions.
 //
 // Converted from CMock to Ztest
+// Original tests from test/cmocka/src/math/numbers/norm_int32.c:
+// Author: Slawomir Blauciak <slawomir.blauciak@linux.intel.com>
 
 #include <zephyr/ztest.h>
 #include <sof/math/numbers.h>