test: skip flaky reload tests on Tarantool 1.10

Since 1.10 is EOLed, it's not worth to spend time on stabilizing
tests for it (especially for complicated scenarios like Cartridge roles
reload).

test/helper.lua

@@ -818,6 +818,12 @@ function helpers.skip_old_tarantool_cartridge_hotreload()
     t.skip_if(luatest_utils.version_ge(tarantool_version, luatest_utils.version(2, 0, 0))
           and luatest_utils.version_ge(luatest_utils.version(2, 5, 1), tarantool_version),
         "Cartridge hotreload tests stuck for vshard 0.1.22+ on Tarantool 2.2, 2.3 and 2.4")
+
+    -- Flaky tests for Tarantool 1.10.15.
+    -- s2-replica | E> ER_READONLY: Can't modify data because this instance is in read-only mode.
+    -- s2-replica | E> ApplyConfigError: Can't modify data because this instance is in read-only mode.
+    t.skip_if(luatest_utils.version_ge(luatest_utils.version(2, 0, 0), tarantool_version),
+        "Flaky tests for Tarantool 1.10.15")
 end
 
 function helpers.build_default_cartridge_cfg(srv_name)