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/CodeGen/debug-info-block-decl.c b/clang/test/CodeGen/debug-info-block-decl.c
index f3f5e6b..5476d88 100644
--- a/clang/test/CodeGen/debug-info-block-decl.c
+++ b/clang/test/CodeGen/debug-info-block-decl.c
@@ -9,8 +9,8 @@
 
 int main()
 {
-// CHECK: [[ASSIGNMENT]] = !MDLocation(line: [[@LINE+2]],
-// CHECK: [[BLOCK_ENTRY]] = !MDLocation(line: [[@LINE+1]],
+// CHECK: [[ASSIGNMENT]] = !DILocation(line: [[@LINE+2]],
+// CHECK: [[BLOCK_ENTRY]] = !DILocation(line: [[@LINE+1]],
     int (^blockptr)(void) = ^(void) {
       return 0;
     };