Test some parser stack overflow panic cases found through fuzzing

V3_GIT_ORIGIN_REV_ID: c9140708c7244546cfab61db2487d62abc51ad38

v3/crates/lang-graphql/tests/README.md

@@ -11,6 +11,9 @@ A few full `parse()` cases were also added from
 [graphql-js tests](https://github.com/graphql/graphql-js/blob/main/src/language/__tests__/parser-test.ts)
 although they were not numerous or very interesting. They are added starting at `ok/1111_*`
 
+Test cases from fuzzing are added into the `err/6xxx_` namespace. In these
+cases a test failure is a panic.
+
 Some `ok` cases that are only valid for the 2021 spec were renamed to `*.2021` and ignored.
 
 # TODO

v3/crates/lang-graphql/tests/query_testdata/err/6000_stackoverflow1.txt

@@ -0,0 +1,11 @@
+Err(
+    Positioned {
+        item: OtherError(
+            "Recursion limit exceeded",
+        ),
+        position: SourcePosition {
+            line: 1,
+            col: 121,
+        },
+    },
+)