[gcc r14-1819] [contrib] validate_failures.py: Improve error output

[gcc r14-1819] [contrib] validate_failures.py: Improve error output

[Maxim Kuvyrkov]

https://gcc.gnu.org/g:7aa47751d23ceaf7a7fa746e30dc3266f6c40ad3

commit r14-1819-g7aa47751d23ceaf7a7fa746e30dc3266f6c40ad3
Author: Thiago Bauermann <thiago.bauermann@linaro.org>
Date:   Thu Jun 1 12:25:18 2023 +0000

    [contrib] validate_failures.py: Improve error output
    
    - Print message in case of broken sum file error.
    - Print error messages to stderr.  The script's stdout is, usually,
      redirected to a file, and error messages shouldn't go there.
    
    contrib/ChangeLog:
    
            * testsuite-management/validate_failures.py (TestResult): Improve error
            output.

Diff:
---
 contrib/testsuite-management/validate_failures.py | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/contrib/testsuite-management/validate_failures.py b/contrib/testsuite-management/validate_failures.py
index 6dcdcf5c69b..1919935cf53 100755
--- a/contrib/testsuite-management/validate_failures.py
+++ b/contrib/testsuite-management/validate_failures.py
@@ -136,12 +136,15 @@ class TestResult(object):
          self.name,
          self.description) = _VALID_TEST_RESULTS_REX.match(summary_line).groups()
       except:
-        print('Failed to parse summary line: "%s"' % summary_line)
+        print('Failed to parse summary line: "%s"' % summary_line,
+              file=sys.stderr)
         raise
       self.ordinal = ordinal
       if tool == None or exp == None:
         # .sum file seem to be broken.  There was no "tool" and/or "exp"
         # lines preceding this result.
+        print(f'.sum file seems to be broken: tool="{tool}", exp="{exp}", summary_line="{summary_line}"',
+              file=sys.stderr)
         raise
       self.tool = tool
       self.exp = exp