GC.stat(x) should always be the same as GC.stat[x]

Author: chrisseaton

spec/ruby/core/gc/stat_spec.rb

@@ -11,6 +11,10 @@
     GC.stat(:count).should be_kind_of(Integer)
   end
 
+  it "returns nil for a non-existent stat" do
+    GC.stat(:does_not_exist).should be_nil
+  end
+
   it "increases count after GC is run" do
     count = GC.stat(:count)
     GC.start

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

@@ -130,12 +130,10 @@ def self.stat(option = nil)
       end
     end
 
-    return stat unless option
-
-    if stat[option]
+    if option
       stat[option]
     else
-      0
+      stat
     end
   end