patch 9.0.1233: search() loops forever if "skip" is TRUE for all matches

Problem:    search() loops forever if "skip" is TRUE for all matches.
Solution:   Keep the position of the first match.

src/evalfunc.c

@@ -8794,7 +8794,8 @@ search_cmn(typval_T *argvars, pos_T *match_pos, int *flagsp)
 	if (subpatnum == FAIL || !use_skip)
 	    // didn't find it or no skip argument
 	    break;
-	firstpos = pos;
+	if (firstpos.lnum == 0)
+	    firstpos = pos;
 
 	// If the skip expression matches, ignore this match.
 	{

src/testdir/test_search.vim

@@ -1411,6 +1411,22 @@ func Test_subst_word_under_cursor()
   set noincsearch
 endfunc
 
+func Test_search_skip_all_matches()
+  enew
+  call setline(1, ['no match here',
+        \ 'match this line',
+        \ 'nope',
+        \ 'match in this line',
+        \ 'last line',
+        \ ])
+  call cursor(1, 1)
+  let lnum = search('this', '', 0, 0, 'getline(".") =~ "this line"')
+  " Only check that no match is found.  Previously it searched forever.
+  call assert_equal(0, lnum)
+
+  bwipe!
+endfunc
+
 func Test_search_undefined_behaviour()
   CheckFeature terminal
 

src/version.c

@@ -695,6 +695,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    1233,
 /**/
     1232,
 /**/