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-decl-nested.cpp b/clang/test/CodeGenCXX/debug-info-decl-nested.cpp
index 6ceb31b..2c35241 100644
--- a/clang/test/CodeGenCXX/debug-info-decl-nested.cpp
+++ b/clang/test/CodeGenCXX/debug-info-decl-nested.cpp
@@ -17,13 +17,13 @@
   public:
     InnerClass(); // Here createContextChain() generates a limited type for OuterClass.
   } theInnerClass;
-// CHECK0: ![[DECL:[0-9]+]] = !MDSubprogram(name: "OuterClass"
+// CHECK0: ![[DECL:[0-9]+]] = !DISubprogram(name: "OuterClass"
 // CHECK0-SAME: line: [[@LINE+2]]
 // CHECK0-SAME: isDefinition: false
   OuterClass(const Foo *); // line 10
 };
 OuterClass::InnerClass OuterClass::theInnerClass; // This toplevel decl causes InnerClass to be generated.
-// CHECK0: !MDSubprogram(name: "OuterClass"
+// CHECK0: !DISubprogram(name: "OuterClass"
 // CHECK0-SAME: line: [[@LINE+3]]
 // CHECK0-SAME: isDefinition: true
 // CHECK0-SAME: declaration: ![[DECL]]
@@ -41,13 +41,13 @@
   public:
     InnerClass1();
   } theInnerClass1;
-// CHECK1: ![[DECL:[0-9]+]] = !MDSubprogram(name: "Bar"
+// CHECK1: ![[DECL:[0-9]+]] = !DISubprogram(name: "Bar"
 // CHECK1-SAME: line: [[@LINE+2]]
 // CHECK1-SAME: isDefinition: false
   void Bar(const Foo1 *);
 };
 OuterClass1::InnerClass1 OuterClass1::theInnerClass1;
-// CHECK1: !MDSubprogram(name: "Bar"
+// CHECK1: !DISubprogram(name: "Bar"
 // CHECK1-SAME: line: [[@LINE+3]]
 // CHECK1-SAME: isDefinition: true
 // CHECK1-SAME: declaration: ![[DECL]]
@@ -64,13 +64,13 @@
   public:
     InnerClass2();
   } theInnerClass2;
-// CHECK2: ![[DECL:[0-9]+]] = !MDSubprogram(name: "~OuterClass2"
+// CHECK2: ![[DECL:[0-9]+]] = !DISubprogram(name: "~OuterClass2"
 // CHECK2-SAME: line: [[@LINE+2]]
 // CHECK2-SAME: isDefinition: false
   ~OuterClass2(); // line 10
 };
 OuterClass2::InnerClass2 OuterClass2::theInnerClass2;
-// CHECK4: !MDSubprogram(name: "~OuterClass2"
+// CHECK4: !DISubprogram(name: "~OuterClass2"
 // CHECK4-SAME: line: [[@LINE+3]]
 // CHECK4-SAME: isDefinition: true
 // CHECK4-SAME: declaration: ![[DECL]]