Fix Windows cppcheck trailing newline normalization

Previous fix wasn't working because we need to normalize both actual and
expected output, not just actual. Now we normalize both when either has
multiple trailing newlines.

Author: pocc

tests/test_hooks.py

@@ -458,11 +458,13 @@ def run_shell_cmd(cmd_name, files, args, _, target_output, target_retcode):
         # Newer cppcheck versions include a checkers report info line
         if cmd_name == "cppcheck":
             actual = re.sub(rb"\nnofile:0:0: information: Active checkers.*\n+", b"\n", actual)
-            # Windows cppcheck adds extra trailing newline
-            actual = actual.rstrip(b"\n") + b"\n" if actual.endswith(b"\n") else actual
         # Windows clang uses return-mismatch instead of return-type
         if cmd_name in ["clang-tidy", "include-what-you-use"]:
             actual = actual.replace(b"clang-diagnostic-return-mismatch", b"clang-diagnostic-return-type")
+        # Normalize trailing newlines for cppcheck on Windows
+        if cmd_name == "cppcheck" and (actual.endswith(b"\n\n") or target_output.endswith(b"\n\n")):
+            actual = actual.rstrip(b"\n") + b"\n"
+            target_output = target_output.rstrip(b"\n") + b"\n"
         retcode = sp_child.returncode
         utils.assert_equal(target_output, actual)
         assert target_retcode == retcode