[Orc] Move Orc code into a namespace (llvm::orc), update Kaleidoscope code.

NFC.

llvm-svn: 230143
diff --git a/llvm/examples/Kaleidoscope/Orc/lazy_codegen/toy.cpp b/llvm/examples/Kaleidoscope/Orc/lazy_codegen/toy.cpp
index 168ebdd..ee42d79 100644
--- a/llvm/examples/Kaleidoscope/Orc/lazy_codegen/toy.cpp
+++ b/llvm/examples/Kaleidoscope/Orc/lazy_codegen/toy.cpp
@@ -19,7 +19,9 @@
 #include <sstream>
 #include <string>
 #include <vector>
+
 using namespace llvm;
+using namespace llvm::orc;
 
 //===----------------------------------------------------------------------===//
 // Lexer