503be69af6
Previously, XhrBackend would call JSON.parse('') if the response body was empty (a 200 status code with content-length 0). This changes the XhrBackend to attempt the JSON parse only if the response body is non-empty. Otherwise, the body is left as null. Fixes #18680. Fixes #19413. Fixes #19502. Fixes #19555. PR Close #19958