re PR go/68141 (go/gofrontend/import-archive.cc: 2 * poor choice of function parameter type ?)

	PR go/68141
    compiler: Use references in Archive_iterator comparison functions.
    
    Fixes minor performance problem pointed out in
    https://gcc.gnu.org/PR68141 .

    Reviewed-on: https://go-review.googlesource.com/17153

From-SVN: r230689

gcc/go/gofrontend/MERGE

-128d5b14b8ab967cb61c01a9b2c596bda7d04c63
+f79db38cf3484b63f7807abef05eecb23e9d0806
 
 The first line of this file holds the git revision number of the last
 merge done from the gofrontend repository.

gcc/go/gofrontend/import-archive.cc

@@ -468,11 +468,11 @@ class Archive_iterator
   }
 
   bool
-  operator==(const Archive_iterator p) const
+  operator==(const Archive_iterator& p) const
   { return this->off_ == p->off; }
 
   bool
-  operator!=(const Archive_iterator p) const
+  operator!=(const Archive_iterator& p) const
   { return this->off_ != p->off; }
 
  private: