Cleaned up results formatter options hand-off.

* --results-formatter-options renamed to --results-formatter-option,
  with short version of -O

* Multiple --results-formatter-option=OPTION can be specified.  The
  comma-separating mechanism has been removed.

* XunitFormatter options modified: -n and -r are now short forms of
  --ignore-skip-name and --ignore-skip-reason.  Those long option
  names were tweaked lightly.  They also can be specified multiple
  times on the command line.  The comma-separating, multiple-pattern-
  per-option mechanism has been removed.

One can now specify:

  dotest.py --results-file stdout -O-ndsym -O-nlldb-mi

for example, to ignore reporting skips for dsym-related or lldb-mi-related
tests in the xUnit report.

llvm-svn: 248384
diff --git a/lldb/test/dotest_args.py b/lldb/test/dotest_args.py
index 481cd64..ba79600 100644
--- a/lldb/test/dotest_args.py
+++ b/lldb/test/dotest_args.py
@@ -172,11 +172,13 @@
               'test events into some kind of meaningful report, written to '
               'the designated output results file-like object'))
     group.add_argument(
-        '--results-formatter-options',
-        action='store',
-        help=('Specify comma-separated options to pass to the formatter. '
-              'Use --results-formatter-options="--option1[,--option2[,...]]" '
-              'syntax.  Note the "=" is critical, and don\'t use whitespace.'))
+        '--results-formatter-option',
+        '-O',
+        action='append',
+        dest='results_formatter_options',
+        help=('Specify an option to pass to the formatter. '
+              'Use --results-formatter-option="--option1=val1" '
+              'syntax.  Note the "=" is critical, don\'t include whitespace.'))
     group.add_argument(
         '--event-add-entries',
         action='store',