patch 8.1.1308: the Normal highlight is not defined when compiled with GUI

Problem:    The Normal highlight is not defined when compiled with GUI.
Solution:   Always define Normal. (Christian Brabandt, closes #4072)
diff --git a/src/syntax.c b/src/syntax.c
index 537794a..0949145 100644
--- a/src/syntax.c
+++ b/src/syntax.c
@@ -6865,6 +6865,7 @@
     "lCursor guibg=fg guifg=bg", /* should be different, but what? */
 #endif
     "default link QuickFixLine Search",
+    CENT("Normal cterm=NONE", "Normal gui=NONE"),
     NULL
 };
 
@@ -6946,9 +6947,6 @@
 #endif
     CENT("MatchParen term=reverse ctermbg=Cyan",
 	 "MatchParen term=reverse ctermbg=Cyan guibg=Cyan"),
-#ifdef FEAT_GUI
-    "Normal gui=NONE",
-#endif
 #ifdef FEAT_TERMINAL
     CENT("StatusLineTerm term=reverse,bold cterm=bold ctermfg=White ctermbg=DarkGreen",
 	 "StatusLineTerm term=reverse,bold cterm=bold ctermfg=White ctermbg=DarkGreen gui=bold guifg=bg guibg=DarkGreen"),
@@ -7042,9 +7040,6 @@
     CENT("Conceal ctermbg=DarkGrey ctermfg=LightGrey",
 	 "Conceal ctermbg=DarkGrey ctermfg=LightGrey guibg=DarkGrey guifg=LightGrey"),
 #endif
-#ifdef FEAT_GUI
-    "Normal gui=NONE",
-#endif
 #ifdef FEAT_TERMINAL
     CENT("StatusLineTerm term=reverse,bold cterm=bold ctermfg=Black ctermbg=LightGreen",
 	 "StatusLineTerm term=reverse,bold cterm=bold ctermfg=Black ctermbg=LightGreen gui=bold guifg=bg guibg=LightGreen"),