patch 9.1.0594: Unnecessary redraw when setting 'winfixbuf'

Problem:  Unnecessary redraw when setting 'winfixbuf'.
Solution: Remove P_RWIN flag. (zeertzjq)

closes: #15283

Signed-off-by: zeertzjq <zeertzjq@outlook.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>
diff --git a/src/testdir/test_goto.vim b/src/testdir/test_goto.vim
index 357a8d2..8813bcb 100644
--- a/src/testdir/test_goto.vim
+++ b/src/testdir/test_goto.vim
@@ -296,6 +296,7 @@
       return x;
     }
   [CODE]
+
   call XTest_goto_decl('gd', lines, 4, 7)
 endfunc
 
@@ -320,14 +321,14 @@
   let pos = getcurpos()
   normal j
   set invhlsearch spell spelllang=en,cjk spelloptions=camel textwidth=80
-  set cursorline cursorcolumn cursorlineopt=line colorcolumn=+1
+  set cursorline cursorcolumn cursorlineopt=line colorcolumn=+1 winfixbuf
   set background=dark
   set background=light
   normal k
   call assert_equal(pos, getcurpos())
   bwipe!
   set hlsearch& spell& spelllang& spelloptions& textwidth&
-  set cursorline& cursorcolumn& cursorlineopt& colorcolumn&
+  set cursorline& cursorcolumn& cursorlineopt& colorcolumn& winfixbuf&
   set background&
 endfunc