patch 8.0.1519: getchangelist() does not use argument as bufname()

Problem:    Getchangelist() does not use argument as bufname().
Solution:   Use get_buf_tv(). (Yegappan Lakshmanan, closes #2641)

Author: brammool

src/evalfunc.c

@@ -4365,7 +4365,10 @@ f_getchangelist(typval_T *argvars, typval_T *rettv)
 	return;
 
 #ifdef FEAT_JUMPLIST
-    buf = find_buffer(&argvars[0]);
+    (void)get_tv_number(&argvars[0]);	    /* issue errmsg if type error */
+    ++emsg_off;
+    buf = get_buf_tv(&argvars[0], FALSE);
+    --emsg_off;
     if (buf == NULL)
 	return;
 

src/testdir/test_changelist.vim

@@ -9,7 +9,7 @@ func Test_getchangelist()
   bwipe!
   enew
   call assert_equal([], getchangelist(10))
-  call assert_equal([[], 0], getchangelist(bufnr('%')))
+  call assert_equal([[], 0], getchangelist('%'))
 
   call writefile(['line1', 'line2', 'line3'], 'Xfile1.txt')
   call writefile(['line1', 'line2', 'line3'], 'Xfile2.txt')
@@ -23,15 +23,15 @@ func Test_getchangelist()
 	      \ {'lnum' : 2, 'col' : 4, 'coladd' : 0},
 	      \ {'lnum' : 4, 'col' : 4, 'coladd' : 0},
 	      \ {'lnum' : 6, 'col' : 4, 'coladd' : 0}], 2],
-	      \ getchangelist(bufnr('%')))
+	      \ getchangelist('%'))
 
   hide edit Xfile2.txt
   exe "normal 1GOline\<C-G>u1.0"
   exe "normal 2Goline\<C-G>u2.0"
   call assert_equal([[
 	      \ {'lnum' : 1, 'col' : 6, 'coladd' : 0},
 	      \ {'lnum' : 3, 'col' : 6, 'coladd' : 0}], 2],
-	      \ getchangelist(bufnr('%')))
+	      \ getchangelist('%'))
   hide enew
 
   call assert_equal([[

src/version.c

@@ -771,6 +771,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    1519,
 /**/
     1518,
 /**/