[TF FE] Extend StringSplitV2 layer tests and fix warnings (openvinotoolkit#24148)

**Details:** Extend StringSplitV2 layer tests and fix warnings. Merge
after openvinotoolkit/openvino_tokenizers#121

**Ticket:** TBD

---------

Signed-off-by: Kazantsev, Roman <roman.kazantsev@intel.com>

Author: rkazants

tests/layer_tests/tensorflow_tests/test_tf_Equal.py

@@ -223,7 +223,7 @@ def _prepare_input(self, inputs_info):
         x_shape = inputs_info['x:0']
         y_shape = inputs_info['y:0']
         inputs_data = {}
-        strings_dictionary = ['UPPER<>CASE SENTENCE', 'lower case\n\s sentence', ' UppEr LoweR CAse SENtence \t\n',
+        strings_dictionary = ['UPPER<>CASE SENTENCE', 'lower case\n sentence', ' UppEr LoweR CAse SENtence \t\n',
                               '  some sentence', 'another sentence HERE    ']
         inputs_data['x:0'] = rng.choice(strings_dictionary, x_shape)
         inputs_data['y:0'] = rng.choice(strings_dictionary, y_shape)

tests/layer_tests/tensorflow_tests/test_tf_StaticRegexReplace.py

@@ -36,7 +36,7 @@ def create_static_regex_replace_net(self, input_shape, pattern, rewrite, replace
         return tf_net, ref_net
 
     @pytest.mark.parametrize('input_shape', [[], [2], [3, 4], [1, 3, 2]])
-    @pytest.mark.parametrize('pattern', ['(\s)|(-)', '[A-Z]{2,}', '^\s+|\s+$'])
+    @pytest.mark.parametrize('pattern', [r'(\s)|(-)', r'[A-Z]{2,}', r'^\s+|\s+$'])
     @pytest.mark.parametrize('rewrite', ['', 'replacement word'])
     @pytest.mark.parametrize('replace_global', [None, True, False])
     @pytest.mark.precommit

tests/layer_tests/tensorflow_tests/test_tf_StringSplitV2.py

@@ -17,7 +17,7 @@ def _prepare_input(self, inputs_info):
         assert 'input:0' in inputs_info
         input_shape = inputs_info['input:0']
         inputs_data = {}
-        strings_dictionary = ['UPPER<>CASE SENTENCE', 'lower case\n\s sentence', ' UppEr LoweR CAse SENtence \t\n',
+        strings_dictionary = ['UPPER<>CASE SENTENCE', 'lower case\n sentence', ' UppEr LoweR CAse SENtence \t\n',
                               '  some sentence', 'another sentence HERE    ']
         inputs_data['input:0'] = rng.choice(strings_dictionary, input_shape)
         return inputs_data
@@ -39,7 +39,7 @@ def create_string_split_v2_net(self, input_shape, sep, maxsplit):
 
     @pytest.mark.parametrize('input_shape', [[1], [2], [5]])
     @pytest.mark.parametrize('sep', ['', '<>'])
-    @pytest.mark.parametrize('maxsplit', [None, -1])
+    @pytest.mark.parametrize('maxsplit', [None, -1, 5, 10])
     @pytest.mark.precommit
     @pytest.mark.nightly
     @pytest.mark.xfail(condition=platform.system() in ('Darwin', 'Linux') and platform.machine() in ['arm', 'armv7l',