Remove a test for a feature not backported to 2.x.

Signed-off-by: Yury-Fridlyand <yury.fridlyand@improving.com>

docs/user/general/datatypes.rst

@@ -434,13 +434,13 @@ String Data Types
 
 A string is a sequence of characters enclosed in either single or double quotes. For example, both 'text' and "text" will be treated as string literal. To use quote characters in a string literal, you can use two quotes of the same type as the enclosing quotes or a backslash symbol (``\``)::
 
-    os> SELECT 'hello', "world", '"hello"', "'world'", '''hello''', """world""", 'I\'m', 'I''m', "I\"m"
+    os> SELECT 'hello', "world", '"hello"', "'world'", '''hello''', """world"""
     fetched rows / total rows = 1/1
-    +-----------+-----------+-------------+-------------+---------------+---------------+----------+----------+----------+
-    | 'hello'   | "world"   | '"hello"'   | "'world'"   | '''hello'''   | """world"""   | 'I\'m'   | 'I''m'   | "I\"m"   |
-    |-----------+-----------+-------------+-------------+---------------+---------------+----------+----------+----------|
-    | hello     | world     | "hello"     | 'world'     | 'hello'       | "world"       | I'm      | I'm      | I"m      |
-    +-----------+-----------+-------------+-------------+---------------+---------------+----------+----------+----------+
+    +-----------+-----------+-------------+-------------+---------------+---------------+
+    | 'hello'   | "world"   | '"hello"'   | "'world'"   | '''hello'''   | """world"""   |
+    |-----------+-----------+-------------+-------------+---------------+---------------|
+    | hello     | world     | "hello"     | 'world'     | 'hello'       | "world"       |
+    +-----------+-----------+-------------+-------------+---------------+---------------+
 
 Boolean Data Types
 ==================