Changed --context short flag to -C in scripts

This matches diff and grep, and avoids lower-case conflicts in
test.py/bench.py.

scripts/bench.py

@@ -1578,7 +1578,7 @@ if __name__ == "__main__":
         default=3,
         help="Show this many test failures. Defaults to 3.")
     bench_parser.add_argument(
-        '--context',
+        '-C', '--context',
         type=lambda x: int(x, 0),
         default=5,
         help="Show this many lines of stdout on bench failure. "

scripts/cov.py

@@ -805,7 +805,7 @@ if __name__ == "__main__":
         action='store_true',
         help="Show uncovered branches.")
     parser.add_argument(
-        '-c', '--context',
+        '-C', '--context',
         type=lambda x: int(x, 0),
         default=3,
         help="Show n additional lines of context. Defaults to 3.")

scripts/perf.py

@@ -1289,7 +1289,7 @@ if __name__ == "__main__":
         help="Show lines with samples above this threshold as a percent of "
             "all lines. Defaults to %s." % ','.join(str(t) for t in THRESHOLD))
     parser.add_argument(
-        '-c', '--context',
+        '-C', '--context',
         type=lambda x: int(x, 0),
         default=3,
         help="Show n additional lines of context. Defaults to 3.")

scripts/perfbd.py

@@ -1274,7 +1274,7 @@ if __name__ == "__main__":
         help="Show lines with erases above this threshold as a percent of "
             "all lines. Defaults to %s." % ','.join(str(t) for t in THRESHOLD))
     parser.add_argument(
-        '-c', '--context',
+        '-C', '--context',
         type=lambda x: int(x, 0),
         default=3,
         help="Show n additional lines of context. Defaults to 3.")

scripts/test.py

@@ -1592,7 +1592,7 @@ if __name__ == "__main__":
         default=3,
         help="Show this many test failures. Defaults to 3.")
     test_parser.add_argument(
-        '--context',
+        '-C', '--context',
         type=lambda x: int(x, 0),
         default=5,
         help="Show this many lines of stdout on test failure. "