patch 8.0.1577: virtual replace test fails on MS-Windows

Problem:    Virtual replace test fails on MS-Windows.
Solution:   Make adding a termcap entry work for a builtin terminal.
            Restore terminal keys in a better way.
diff --git a/src/term.c b/src/term.c
index 5e7aeec..622491f 100644
--- a/src/term.c
+++ b/src/term.c
@@ -2278,6 +2278,7 @@
 	    if (termp->bt_string != NULL)	/* found it */
 	    {
 		key = TERMCAP2KEY(name[0], name[1]);
+		++termp;
 		while (termp->bt_entry != (int)KS_NAME)
 		{
 		    if ((int)termp->bt_entry == key)