[committed][gdb/testsuite] Don't leak tuiterm.exp spawn override

[Andreas Schwab]

On Jun 17 2020, Tom de Vries wrote:

> do_this {
>     puts "2: {"
> }

This is unbalanced.  Since double quotes are not special in brace
enclosed strings, the close brace matches the open brace in the second
line, not the first one.  If you want to include a lone brace in a tcl
string, you need to write it with double quotes.

Andreas.

-- 
Andreas Schwab, schwab@linux-m68k.org
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