[Truffle] Adding Array#sort_by! to array.rb.

Author: bjfish

spec/truffle/tags/core/array/sort_by_tags.txt

@@ -1,7 +1,2 @@
-fails:Array#sort_by! sorts array in place by passing each element to the given block
-fails:Array#sort_by! returns an Enumerator if not given a block
-fails:Array#sort_by! completes when supplied a block that always returns the same result
-fails:Array#sort_by! raises a RuntimeError on a frozen array
-fails:Array#sort_by! raises a RuntimeError on an empty frozen array
 fails:Array#sort_by! returns the specified value when it would break in the given block
 fails:Array#sort_by! makes some modification even if finished sorting when it would break in the given block

truffle/src/main/ruby/core/rubinius/common/array.rb

@@ -1080,6 +1080,14 @@ def transpose
     out
   end
 
+  def sort_by!(&block)
+    Rubinius.check_frozen
+
+    return to_enum :sort_by! unless block_given?
+
+    replace sort_by(&block)
+  end
+
   # Insertion sort in-place between the given indexes.
   def isort!(left, right)
     i = left + 1