repl: make invalid RegExps throw in the REPL

Fixes #2746.

lib/repl.js

@@ -271,6 +271,9 @@ function REPLServer(prompt, stream, eval_, useGlobal, ignoreUndefined) {
       // Convert error to string
       e = e && (e.stack || e.toString());
       return e && e.match(/^SyntaxError/) &&
+             // RegExp syntax error
+             !e.match(/^SyntaxError: Invalid regular expression/) &&
+             // JSON.parse() error
              !(e.match(/^SyntaxError: Unexpected token .*\n/) &&
              e.match(/\n    at Object.parse \(native\)\n/));
     }

test/simple/test-repl.js

@@ -126,6 +126,10 @@ function error_test() {
     // should throw
     { client: client_unix, send: 'JSON.parse(\'{invalid: \\\'json\\\'}\');',
       expect: /^SyntaxError: Unexpected token i/ },
+    // invalid RegExps are a special case of syntax error,
+    // should throw
+    { client: client_unix, send: '/(/;',
+      expect: /^SyntaxError: Invalid regular expression\:/ },
     // Named functions can be used:
     { client: client_unix, send: 'function blah() { return 1; }',
       expect: prompt_unix },