refactor(expect): factor common Expect failure cases into `handle-arguments.inc`

This change factors common Expect failure cases like timeouts and
premature EOFs into the common `handle-arguments.inc` Expect script
fragment.

This fragment now implicitly inserts a timeout handler and an EOF
handler into every expectation introduced after the inclusion of this
fragment. These handlers have the lowest priority, so can be overridden
if necessary.

Signed-off-by: Chris Kay <chris.kay@arm.com>
Change-Id: Ia92f0046ea123d3ed213aa76dc5fce6163471451
(cherry picked from commit 3d2ae3340a4d3682ced971185a14873c03ff3b18)
diff --git a/expect/tftf.exp b/expect/tftf.exp
index 87a5f33..2b1ed24 100644
--- a/expect/tftf.exp
+++ b/expect/tftf.exp
@@ -1,5 +1,5 @@
 #
-# Copyright (c) 2019-2020 Arm Limited. All rights reserved.
+# Copyright (c) 2019-2022 Arm Limited. All rights reserved.
 #
 # SPDX-License-Identifier: BSD-3-Clause
 #
@@ -26,9 +26,6 @@
 		expect_string "Exiting tests." "<<TFTF Fail>>"
 		exit_uart -1
 	}
-	timeout {
-		exit_timeout
-	}
 }
 
 exit_uart -1