twister: blackbox: coverage: fix matching pattern

Fix the expected pattern randomly matched to coverage.json contents
ordered differently at test_coverage_basedir().

Signed-off-by: Dmitrii Golovanov <dmitrii.golovanov@intel.com>

scripts/tests/twister_blackbox/test_coverage.py

@@ -47,7 +47,7 @@ class TestCoverage:
                 'coverage.log', 'coverage.json',
                 'coverage'
             ],
-            r'{"files": \[], "gcovr/format_version": ".*"}'
+            r'{"files": \[\], "gcovr/format_version": ".*"}'
         ),
     ]
     TESTDATA_4 = [
@@ -244,7 +244,7 @@ class TestCoverage:
                 with open(path, "r") as json_file:
                     json_content = json.load(json_file)
                     pattern = re.compile(expected_content)
-                    assert pattern.match(json.dumps(json_content))
+                    assert pattern.match(json.dumps(json_content, sort_keys=True))
         if os.path.exists(base_dir):
             os.rmdir(base_dir)