patch 8.2.1577: Vim9: hasmapto()/mapcheck()/maparg() do nottake "true" arg

Problem:    Vim9: hasmapto(), mapcheck() and maparg() do not take "true" as
            argument.
Solution:   Use tv_get_bool(). (closes #6822, closes #6824)
diff --git a/src/map.c b/src/map.c
index dd3139d..eed3a55 100644
--- a/src/map.c
+++ b/src/map.c
@@ -2204,9 +2204,9 @@
 	which = tv_get_string_buf_chk(&argvars[1], buf);
 	if (argvars[2].v_type != VAR_UNKNOWN)
 	{
-	    abbr = (int)tv_get_number(&argvars[2]);
+	    abbr = (int)tv_get_bool(&argvars[2]);
 	    if (argvars[3].v_type != VAR_UNKNOWN)
-		get_dict = (int)tv_get_number(&argvars[3]);
+		get_dict = (int)tv_get_bool(&argvars[3]);
 	}
     }
     else