New test code failed to close the file. This caused

test_file to fail on Windows in reality (can't delete
a still-open file), but a new bare "except:" hid that
test_file failed on Windows, and leaving behind the
still-open TESTFN caused a cascade of bogus failures
in later tests.

So, close the file, and stop hiding failure to unlink.

Lib/test/test_file.py

@@ -323,6 +323,7 @@ try:
                          "failed. Got %r, expected %r" % (line, testline))
     # Reading after iteration hit EOF shouldn't hurt either
     f = open(TESTFN)
+    try:
         for line in f:
             pass
         try:
@@ -332,9 +333,7 @@ try:
             f.readlines()
         except ValueError:
             raise TestFailed("read* failed after next() consumed file")
+    finally:
+        f.close()
 finally:
-    # Bare 'except' so as not to mask errors in the test
-    try:
     os.unlink(TESTFN)
-    except:
-        pass