patch 9.0.0234: cannot make difference between :normal end and argument char

Problem:    Cannot make difference between the end of :normal and a character
            in its argument.
Solution:   Add the "typebuf_was_empty" flag. (closes #10950)
diff --git a/src/getchar.c b/src/getchar.c
index c7601ef..4134eb9 100644
--- a/src/getchar.c
+++ b/src/getchar.c
@@ -3056,7 +3056,10 @@
     ++vgetc_busy;
 
     if (advance)
+    {
 	KeyStuffed = FALSE;
+	typebuf_was_empty = FALSE;
+    }
 
     init_typebuf();
     start_stuff();
@@ -3361,6 +3364,10 @@
 #ifdef FEAT_CMDWIN
 		    tc = c;
 #endif
+		    // set a flag to indicate this wasn't a normal char
+		    if (advance)
+			typebuf_was_empty = TRUE;
+
 		    // return from main_loop()
 		    if (pending_exmode_active)
 			exmode_active = EXMODE_NORMAL;