src: remove --expose-http2 option

This commit removes the --expose-http2 option. In the code comment it
states that this should should be noop through v9.x, and it sounds like
it can be removed for 10.x and above.

src/node.cc

@@ -3357,7 +3357,6 @@ static void CheckIfAllowedInEnv(const char* exe, bool is_env,
     "--experimental-modules",
     "--experimental-repl-await",
     "--experimental-vm-modules",
-    "--expose-http2",   // keep as a non-op through v9.x
     "--force-fips",
     "--icu-data-dir",
     "--inspect",
@@ -3607,9 +3606,6 @@ static void ParseArgs(int* argc,
     } else if (strcmp(arg, "--expose-internals") == 0 ||
                strcmp(arg, "--expose_internals") == 0) {
       config_expose_internals = true;
-    } else if (strcmp(arg, "--expose-http2") == 0 ||
-               strcmp(arg, "--expose_http2") == 0) {
-      // Keep as a non-op through v9.x
     } else if (strcmp(arg, "-") == 0) {
       break;
     } else if (strcmp(arg, "--") == 0) {

test/parallel/test-http2-https-fallback-http-server-options.js

@@ -1,4 +1,3 @@
-// Flags: --expose-http2
 'use strict';
 
 const common = require('../common');