runtime(syntax-tests): Clear and redraw the ruler line with the shell info

The current contents of sh_01_99.dump and sh_09_99.dump
begin with ":redraw" in the ruler line whereas both the
comment and the need for the redraw command execution imply
blanks "       ".

related: #15150

Signed-off-by: Aliaksei Budavei <0x000c70@gmail.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>

runtime/syntax/testdir/dumps/sh_01_99.dump

@@ -17,4 +17,4 @@
 |~| @73
 |~| @73
 |~| @73
-|:+0#0000000&|r|e|d|r|a|w| @49|4|,|1| @10|A|l@1| 
+| +0#0000000&@56|4|,|1| @10|A|l@1| 

runtime/syntax/testdir/dumps/sh_09_99.dump

@@ -17,4 +17,4 @@
 |(+0#e000e06&| |c+0#af5f00255&|d| +0#e000e06&|$|{|H|O|M|E|}| |)| +0#0000000&||| |w|c| |-+0#e000e06&|c| +0#0000000&@52
 |(|(+0#e000e06&|n+0#00e0e07&|=+0#0000000&|1+0#e000002&|+|2|)+0#e000e06&|)+0#ffffff16#ff404010| +0#0000000#ffffff0@65
 >l+0#af5f00255&|e|t| +0#0000000&|n+0#00e0e07&|=+0#0000000&|1+0#e000002&|++0#0000000&|2+0#e000002&| +0#0000000&@65
-|:|r|e|d|r|a|w| @49|1|9|,|1| @9|A|l@1| 
+@57|1|9|,|1| @9|A|l@1| 

runtime/syntax/testdir/runtest.vim

@@ -307,7 +307,7 @@ func RunTest()
 
       " Clear the shell info if there are not enough lines to cause a scroll
       if filetype == 'sh' && IsWinNumOneAtEOF(in_name_and_out_name)
-	call term_sendkeys(buf, ":redraw\<CR>")
+	call term_sendkeys(buf, ":redraw!\<CR>")
       endif
 
       " Make a Screendump every 18 lines of the file: failed/root_NN.dump