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/field-access-debug-info.cpp b/clang/test/CodeGenCXX/field-access-debug-info.cpp
index 23a27d3..38c06f1 100644
--- a/clang/test/CodeGenCXX/field-access-debug-info.cpp
+++ b/clang/test/CodeGenCXX/field-access-debug-info.cpp
@@ -1,10 +1,10 @@
 // RUN: %clang -g -S -emit-llvm %s -o - | FileCheck %s
 
-// CHECK: !MDDerivedType(tag: DW_TAG_member, name: "p"
+// CHECK: !DIDerivedType(tag: DW_TAG_member, name: "p"
 // CHECK-SAME:           baseType: ![[INT:[0-9]+]]
 // CHECK-SAME:           DIFlagPublic
-// CHECK: ![[INT]] = !MDBasicType(name: "int"
-// CHECK: !MDDerivedType(tag: DW_TAG_member, name: "pr"
+// CHECK: ![[INT]] = !DIBasicType(name: "int"
+// CHECK: !DIDerivedType(tag: DW_TAG_member, name: "pr"
 // CHECK-NOT:            flags:
 // CHECK-SAME:           baseType: ![[INT]]