testsuite: Properly quote dejagnu negative line numbers

testsuite: Properly quote dejagnu negative line numbers

Some testcases specifically test for negative line numbers. Those tests with
bare line numbers may be parsed incorrectly by Tcl/Expect as invalid options.
This patch encloses the negative numbers in braces so that they are
recognized as an optional parameter.

gcc/testsuite/ChangeLog

2020-07-02  David Edelsohn  <dje.gcc@gmail.com>

	* gcc.dg/fixits-pr84852-1.c: Enclose negative line number in braces.
	* gcc.dg/fixits-pr84852-2.c: Same.
	* gcc.dg/pr89410-1.c: Same.
	* gcc.dg/pr89410-2.c: Same.