Remove sil option flags that are no longer needed.

Swift SVN r25828

include/swift/AST/SILOptions.h

@@ -48,9 +48,6 @@ public:
   /// Remove all runtime assertions during optimizations.
   bool RemoveRuntimeAsserts = false;
 
-  /// Controls whether the SIL ARC optimizations are run.
-  bool EnableARCOptimizations = true;
-
   /// Controls whether or not paranoid verification checks are run.
   bool VerifyAll = false;
 
@@ -86,9 +83,6 @@ public:
   /// Should we print out instruction counts if -print-stats is passed in?
   bool PrintInstCounts = false;
 
-  /// Should we optimize function signatures?
-  bool EnableFuncSigOpts = true;
-
   /// Should we emit self as a guaranteed parameter?
   bool EnableGuaranteedSelf = false;