[Cleanup] Delete deprecated FunctionTemplate::GetFunction API.

BUG=v8:7295,v8:8562

Change-Id: Ifa02ba233967ba38d4ff43576de77738001d076a
Reviewed-on: https://chromium-review.googlesource.com/c/1450115Reviewed-by: Yang Guo <yangguo@chromium.org>
Commit-Queue: Ross McIlroy <rmcilroy@chromium.org>
Cr-Commit-Position: refs/heads/master@{#59330}

include/v8.h

@@ -5935,7 +5935,6 @@ class V8_EXPORT FunctionTemplate : public Template {
       SideEffectType side_effect_type = SideEffectType::kHasSideEffect);
 
   /** Returns the unique function instance in the current execution context.*/
-  V8_DEPRECATED("Use maybe version", Local<Function> GetFunction());
   V8_WARN_UNUSED_RESULT MaybeLocal<Function> GetFunction(
       Local<Context> context);
 

src/api.cc

@@ -6267,14 +6267,6 @@ MaybeLocal<v8::Function> FunctionTemplate::GetFunction(Local<Context> context) {
   RETURN_ESCAPED(result);
 }
 
-
-Local<v8::Function> FunctionTemplate::GetFunction() {
-  Local<Context> context =
-      reinterpret_cast<v8::Isolate*>(Utils::OpenHandle(this)->GetIsolate())
-          ->GetCurrentContext();
-  RETURN_TO_LOCAL_UNCHECKED(GetFunction(context), Function);
-}
-
 MaybeLocal<v8::Object> FunctionTemplate::NewRemoteInstance() {
   auto self = Utils::OpenHandle(this);
   i::Isolate* isolate = self->GetIsolate();