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

NFC.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@230143 91177308-0d34-0410-b5e6-96231b3b80d8

include/llvm/ExecutionEngine/Orc/ObjectLinkingLayer.h

@@ -22,6 +22,7 @@
 #include <memory>
 
 namespace llvm {
+namespace orc {
 
 class ObjectLinkingLayerBase {
 protected:
@@ -260,6 +261,7 @@ private:
   CreateRTDyldMMFtor CreateMemoryManager;
 };
 
-} // end namespace llvm
+} // End namespace orc.
+} // End namespace llvm
 
 #endif // LLVM_EXECUTIONENGINE_ORC_OBJECTLINKINGLAYER_H