patch 8.1.2051: double-click test is a bit flaky

Problem:    Double-click test is a bit flaky.
Solution:   Correct entry in list of flaky tests.

src/testdir/runtest.vim

@@ -333,7 +333,7 @@ let s:flaky_tests = [
       \ 'Test_raw_one_time_callback()',
       \ 'Test_reltime()',
       \ 'Test_server_crash()',
-      \ 'Test_term_mouse_double_click_to_create_tab',
+      \ 'Test_term_mouse_double_click_to_create_tab()',
       \ 'Test_terminal_ansicolors_default()',
       \ 'Test_terminal_ansicolors_func()',
       \ 'Test_terminal_ansicolors_global()',

src/version.c

@@ -757,6 +757,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    2051,
 /**/
     2050,
 /**/