Add skip for newly-added test

The test fails on MixedClusterClientYamlTestSuiteIT because 2.x still
has the infinite loop until backport.

Signed-off-by: Michael Froh <froh@amazon.com>

rest-api-spec/src/main/resources/rest-api-spec/test/index/90_flat_object.yml

@@ -62,6 +62,22 @@ setup:
           },
           "required_matches": 1
         }
+  # Do index refresh
+  - do:
+      indices.refresh:
+        index: test
+
+---
+# Delete Index when connection is teardown
+teardown:
+  - do:
+      indices.delete:
+        index: test
+---
+"Invalid docs":
+  - skip:
+      version: "- 2.99.99"
+      reason: "parsing of these objects would infinite loop prior to 2.18"
   # The following documents are invalid.
   - do:
       catch: /parsing_exception/
@@ -70,7 +86,7 @@ setup:
         id: 3
         body: {
           "ISBN13": "V12154942123242",
-          "catalog": ["Arrays in Action"],
+          "catalog": [ "Arrays in Action" ],
           "required_matches": 1
         }
   - do:
@@ -103,18 +119,6 @@ setup:
           "catalog": [ 12345 ],
           "required_matches": 1
         }
-  # Do index refresh
-  - do:
-      indices.refresh:
-        index: test
-
----
-# Delete Index when connection is teardown
-teardown:
-  - do:
-      indices.delete:
-        index: test
-
 ---
 # Verify that mappings under the catalog field did not expand
 # and no dynamic fields were created.