DebugInfo: Metadata constructs now start with DI*

LLVM r236120 renamed debug info IR constructs to use a `DI` prefix, now
that the `DIDescriptor` hierarchy has been gone for about a week.  This
commit was generated using the rename-md-di-nodes.sh upgrade script
attached to PR23080, followed by running clang-format-diff.py on the
`lib/` portion of the patch.

llvm-svn: 236121
diff --git a/clang/test/CodeGenCXX/debug-info-rvalue-ref.cpp b/clang/test/CodeGenCXX/debug-info-rvalue-ref.cpp
index 797e170..00b5bcc 100644
--- a/clang/test/CodeGenCXX/debug-info-rvalue-ref.cpp
+++ b/clang/test/CodeGenCXX/debug-info-rvalue-ref.cpp
@@ -8,5 +8,5 @@
   printf("%d\n", i);
 }
 
-// CHECK: !MDDerivedType(tag: DW_TAG_rvalue_reference_type, baseType: ![[INT:[0-9]+]])
-// CHECK: ![[INT]] = !MDBasicType(name: "int"
+// CHECK: !DIDerivedType(tag: DW_TAG_rvalue_reference_type, baseType: ![[INT:[0-9]+]])
+// CHECK: ![[INT]] = !DIBasicType(name: "int"