[api] Promote RegisterDefaultSignalHandler to DEPRECATED

R=yangguo@chromium.org

Bug: v8:8238
Change-Id: I657ec92031ffe8241eaac67ba207bddc989c73a7
Reviewed-on: https://chromium-review.googlesource.com/c/1349234Reviewed-by: Yang Guo <yangguo@chromium.org>
Commit-Queue: Andreas Haas <ahaas@chromium.org>
Cr-Commit-Position: refs/heads/master@{#57787}

include/v8.h

@@ -8500,8 +8500,8 @@ class V8_EXPORT V8 {
    * Enable the default signal handler rather than using one provided by the
    * embedder.
    */
-  V8_DEPRECATE_SOON("Use EnableWebAssemblyTrapHandler",
-                    static bool RegisterDefaultSignalHandler());
+  V8_DEPRECATED("Use EnableWebAssemblyTrapHandler",
+                static bool RegisterDefaultSignalHandler());
 
   /**
    * Activate trap-based bounds checking for WebAssembly.