Draft: fix tests for log2_approx and log2_approx64

• skip the test log2_approx.complete when using ctest
  • this test takes too much time to run
• fix test log2_approx64.boundaries
  • The test was actually never executed correctly (unsigned -10 is never <= 10), and log2_approx64_ref() was not accurate enough.
  • Therefore replace it by directly comparing one value above and one value below each rounding boundary.
• add test log2_approx.boundaries

openair1/PHY/TOOLS/tests/CMakeLists.txt

@@ -14,4 +14,4 @@ add_executable(test_log2_approx test_log2_approx.cpp ../log2_approx.c)
 target_link_libraries(test_log2_approx PRIVATE GTest::gtest LOG minimal_lib)
 add_dependencies(tests test_log2_approx)
 add_test(NAME test_log2_approx
-  COMMAND ./test_log2_approx)
+  COMMAND ./test_log2_approx --gtest_filter=-log2_approx.complete)