build: Add TEST_EXCLUDE_COMPONENTS

To exclude during the build process of unit tests some components.

docs/en/api-guides/build-system.rst

@@ -124,6 +124,7 @@ These variables all have default values that can be overridden for custom behavi
 - ``EXTRA_COMPONENT_DIRS``: Optional list of additional directories to search for components.
 - ``COMPONENTS``: A list of component names to build into the project. Defaults to all components found in the COMPONENT_DIRS directories.
 - ``EXCLUDE_COMPONENTS``: Optional list of component names to exclude during the build process. Note that this decreases build time, but not binary size.
+- ``TEST_EXCLUDE_COMPONENTS``: Optional list of component names to exclude during the build process of unit tests.
 
 Any paths in these Makefile variables should be absolute paths. You can convert relative paths using ``$(PROJECT_PATH)/xxx``, ``$(IDF_PATH)/xxx``, or use the Make function ``$(abspath xxx)``.
 

docs/en/api-guides/unit-tests.rst

@@ -120,6 +120,7 @@ Change into tools/unit-test-app directory to configure and build it:
 
 * `make TESTS_ALL=1` - build unit test app with tests for each component having tests in the ``test`` subdirectory.
 * `make TEST_COMPONENTS='xxx'` - build unit test app with tests for specific components. 
+* `make TESTS_ALL=1 TEST_EXCLUDE_COMPONENTS='xxx'` - build unit test app with all unit tests, except for unit tests of some components. (For instance: `make TESTS_ALL=1 TEST_EXCLUDE_COMPONENTS='ulp mbedtls'` - build all unit tests exludes ulp and mbedtls components).
 
 When the build finishes, it will print instructions for flashing the chip. You can simply run ``make flash`` to flash all build output.