patch 9.0.0352: using :echowindow in a timer clears part of message

Problem:    using :echowindow in a timer clears part of message
Solution:   Do not use msg_clr_eos().
diff --git a/src/testdir/dumps/Test_echowindow_2.dump b/src/testdir/dumps/Test_echowindow_2.dump
index f8bea0c..58b2f3f 100644
--- a/src/testdir/dumps/Test_echowindow_2.dump
+++ b/src/testdir/dumps/Test_echowindow_2.dump
@@ -5,4 +5,4 @@
 |═+0#e000002&@74
 |f|i|r|s|t| |l|i|n|e| @64
 |s|e|c|o|n|d| |l|i|n|e| @63
-| +0#0000000&@56|1|,|1| @10|A|l@1| 
+|:+0#0000000&|c|a|l@1| |S|h|o|w|M|e|s@1|a|g|e|(|'|s|e|c|o|n|d| |l|i|n|e|'|)| @24|1|,|1| @10|A|l@1|