Add spec for Regexp.linear_time? + binary Regexp

Author: eregon

spec/ruby/core/regexp/linear_time_spec.rb

@@ -7,6 +7,10 @@
       Regexp.linear_time?('a').should == true
     end
 
+    it "returns true if matching can be done in linear time for a binary Regexp" do
+      Regexp.linear_time?(/[\x80-\xff]/n).should == true
+    end
+
     it "return false if matching can't be done in linear time" do
       Regexp.linear_time?(/(a)\1/).should == false
       Regexp.linear_time?("(a)\\1").should == false