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/linetable-fnbegin.cpp b/clang/test/CodeGenCXX/linetable-fnbegin.cpp
index f579de1..1f752ff 100644
--- a/clang/test/CodeGenCXX/linetable-fnbegin.cpp
+++ b/clang/test/CodeGenCXX/linetable-fnbegin.cpp
@@ -4,12 +4,12 @@
 // CHECK: define{{.*}}bar
 // CHECK-NOT: define
 // CHECK: ret {{.*}}, !dbg [[DBG:.*]]
-// CHECK: [[HPP:.*]] = !MDFile(filename: "./template.hpp",
-// CHECK: [[SP:.*]] = !MDSubprogram(name: "bar",
+// CHECK: [[HPP:.*]] = !DIFile(filename: "./template.hpp",
+// CHECK: [[SP:.*]] = !DISubprogram(name: "bar",
 // CHECK-SAME:                      file: [[HPP]], line: 22
 // CHECK-SAME:                      isDefinition: true
 // We shouldn't need a lexical block for this function.
-// CHECK: [[DBG]] = !MDLocation(line: 23, scope: [[SP]])
+// CHECK: [[DBG]] = !DILocation(line: 23, scope: [[SP]])
 
 
 # 1 "./template.h" 1