bpo-30871: Add test.pythoninfo

* Add Lib/test/pythoninfo.py: script collecting various informations
  about Python to help debugging test failures.
* regrtest: remove sys.hash_info and sys.flags from header.
* Travis CI, Appveyor: run pythoninfo before tests

.github/appveyor.yml

@@ -7,6 +7,7 @@ branches:
     - buildbot-custom
 build_script:
 - cmd: PCbuild\build.bat -e
+- cmd: PCbuild\win32\python.exe -m test.pythoninfo
 test_script:
 - cmd: PCbuild\rt.bat -q -uall -u-cpu -rwW --slowest --timeout=1200 --fail-env-changed -j0
 environment:

.travis.yml

@@ -60,6 +60,7 @@ matrix:
             # Need a venv that can parse covered code.
             ./python -m venv venv
             ./venv/bin/python -m pip install -U coverage
+            ./venv/bin/python -m test.pythoninfo
       script:
         # Skip tests that re-run the entire test suite.
         - ./venv/bin/python -m coverage run --pylib -m test -uall,-cpu -x test_multiprocessing_fork -x test_multiprocessing_forkserver -x test_multiprocessing_spawn
@@ -87,6 +88,7 @@ before_script:
         echo "$changes"
         exit 1
       fi
+      ./python -m test.pythoninfo
 
 script:
   # Using the built Python as patchcheck.py is built around the idea of using

Lib/test/libregrtest/main.py

@@ -424,16 +424,13 @@ def display_header(self):
         print("==", platform.python_implementation(), *sys.version.split())
         print("==", platform.platform(aliased=True),
                       "%s-endian" % sys.byteorder)
-        print("== hash algorithm:", sys.hash_info.algorithm,
-              "64bit" if sys.maxsize > 2**32 else "32bit")
         print("== cwd:", os.getcwd())
         cpu_count = os.cpu_count()
         if cpu_count:
             print("== CPU count:", cpu_count)
         print("== encodings: locale=%s, FS=%s"
               % (locale.getpreferredencoding(False),
                  sys.getfilesystemencoding()))
-        print("Testing with flags:", sys.flags)
 
     def run_tests(self):
         # For a partial run, we do not need to clutter the output.