[api] Advance old variant of v8::RegExp::New to deprecated.

R=adamk@chromium.org

Bug: v8:7293
Cq-Include-Trybots: master.tryserver.chromium.linux:linux_chromium_rel_ng
Change-Id: I308fb8e87e6760664a33f3216af7a484ad1404c4
Reviewed-on: https://chromium-review.googlesource.com/864148Reviewed-by: Adam Klein <adamk@chromium.org>
Commit-Queue: Yang Guo <yangguo@chromium.org>
Cr-Commit-Position: refs/heads/master@{#50681}

include/v8.h

@@ -4877,9 +4877,8 @@ class V8_EXPORT RegExp : public Object {
    *               static_cast<RegExp::Flags>(kGlobal | kMultiline))
    * is equivalent to evaluating "/foo/gm".
    */
-  static V8_DEPRECATE_SOON("Use maybe version",
-                           Local<RegExp> New(Local<String> pattern,
-                                             Flags flags));
+  static V8_DEPRECATED("Use maybe version",
+                       Local<RegExp> New(Local<String> pattern, Flags flags));
   static V8_WARN_UNUSED_RESULT MaybeLocal<RegExp> New(Local<Context> context,
                                                       Local<String> pattern,
                                                       Flags flags);