Always split String#split and Truffle::Splitter.split

Author: andrykonchin

src/main/ruby/truffleruby/core/splitter.rb

@@ -88,6 +88,7 @@ def split(string, pattern, limit, &orig_block)
 
         orig_block ? string : result
       end
+      Truffle::Graal.always_split(instance_method(:split))
 
       private
 

src/main/ruby/truffleruby/core/string.rb

@@ -320,6 +320,7 @@ def scan(pattern, &block)
   def split(pattern = nil, limit = undefined, &block)
     Truffle::Splitter.split(Primitive.dup_as_string_instance(self), pattern, limit, &block)
   end
+  Truffle::Graal.always_split(instance_method(:split))
 
   def squeeze(*strings)
     str = Primitive.dup_as_string_instance(self)