[sil-aa] Compile out DisableAliasAnalysis flag when not building Debug. Put in a comment making it clear that it should be removed once AA bringup is complete.

Swift SVN r13664

lib/SILAnalysis/AliasAnalysis.cpp

@@ -23,11 +23,15 @@
 
 using namespace swift;
 
+#ifndef NDEBUG
+/// This is meant to be used during AA bring up. If AA has been brought up, feel
+/// free to remove this.
 static llvm::cl::opt<bool>
 DisableAliasAnalysis("disable-aa", llvm::cl::init(false),
                      llvm::cl::Hidden,
                      llvm::cl::desc("Always return most conservative AA "
                                     "result."));
+#endif
 
 //===----------------------------------------------------------------------===//
 //                             Utility Functions