Add YAML parser to Support.

llvm-svn: 153977
diff --git a/llvm/test/YAMLParser/duplicate-merge-key.former-loader-error.data b/llvm/test/YAMLParser/duplicate-merge-key.former-loader-error.data
new file mode 100644
index 0000000..6b12764
--- /dev/null
+++ b/llvm/test/YAMLParser/duplicate-merge-key.former-loader-error.data
@@ -0,0 +1,6 @@
+# RUN: yaml-bench -canonical %s
+
+---
+<<: {x: 1, y: 2}
+foo: bar
+<<: {z: 3, t: 4}