patch 9.0.1619: the focus gained/lost escape sequences cause trouble

Problem:    The focus gained/lost escape sequences cause trouble for a
            terminal where Vim does not expect them.
Solution:   Always recognize the codes for focus gained/lost. (closes #12499)
diff --git a/src/term.c b/src/term.c
index 2f0a0cb..0416acc 100644
--- a/src/term.c
+++ b/src/term.c
@@ -2221,7 +2221,9 @@
     // We hard-code the received escape sequences here.  There are the terminfo
     // entries kxIN and kxOUT, but they are rarely used and do hot have a
     // two-letter termcap name.
-    if (use_xterm_like_mouse(term))
+    // This used to be done only for xterm-like terminals, but some others also
+    // may produce these codes.  Always recognize them, as the chance of them
+    // being used for something else is very small.
     {
 	char_u name[3];
 
@@ -6447,7 +6449,7 @@
 # endif // !USE_ON_FLY_SCROLL
 #endif // FEAT_GUI
 
-#if (defined(UNIX) || defined(VMS))
+#if defined(UNIX) || defined(VMS)
 	/*
 	 * Handle FocusIn/FocusOut event sequences reported by XTerm.
 	 * (CSI I/CSI O)