[flags] Remove reference to --js-arguments

The --js-arguments flag is gone since https://crrev.com/c/1291469.
This CL removes a remaining reference to that, and as a drive-by
changes the proposed '--noflag' to '--no-flag'.

R=petermarshall@chromium.org

Bug: v8:8834
Change-Id: I69a8d008e87949d64329b4350197ba0651b54340
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1558087Reviewed-by: Peter Marshall <petermarshall@chromium.org>
Commit-Queue: Clemens Hammacher <clemensh@chromium.org>
Cr-Commit-Position: refs/heads/master@{#60720}

src/flags.cc

@@ -308,11 +308,7 @@ static void SplitArgument(const char* arg, char* buffer, int buffer_size,
     arg++;  // remove 1st '-'
     if (*arg == '-') {
       arg++;  // remove 2nd '-'
-      if (arg[0] == '\0') {
-        const char* kJSArgumentsFlagName = "js_arguments";
-        *name = kJSArgumentsFlagName;
-        return;
-      }
+      DCHECK_NE('\0', arg[0]);  // '--' arguments are handled in the caller.
     }
     if (arg[0] == 'n' && arg[1] == 'o') {
       arg += 2;  // remove "no"
@@ -587,11 +583,10 @@ void FlagList::PrintHelp() {
         "The following syntax for options is accepted (both '-' and '--' are "
         "ok):\n"
         "  --flag        (bool flags only)\n"
-        "  --noflag      (bool flags only)\n"
+        "  --no-flag     (bool flags only)\n"
         "  --flag=value  (non-bool flags only, no spaces around '=')\n"
         "  --flag value  (non-bool flags only)\n"
-        "  --            (equivalent to --js_arguments, captures all remaining "
-        "args)\n\n"
+        "  --            (captures all remaining args in JavaScript)\n\n"
         "Options:\n";
 
   for (const Flag& f : flags) {

src/flags.h

@@ -40,10 +40,10 @@ class V8_EXPORT_PRIVATE FlagList {
   // The following syntax for flags is accepted (both '-' and '--' are ok):
   //
   //   --flag        (bool flags only)
-  //   --noflag      (bool flags only)
+  //   --no-flag     (bool flags only)
   //   --flag=value  (non-bool flags only, no spaces around '=')
   //   --flag value  (non-bool flags only)
-  //   --            (equivalent to --js_arguments, captures all remaining args)
+  //   --            (capture all remaining args in JavaScript)
   static int SetFlagsFromCommandLine(int* argc,
                                      char** argv,
                                      bool remove_flags);