Use `mktemp` in `binaries/strix_tlsf_file.sh`

[lou1306]

Currently strix_tlsf_file.sh writes out the LTL formula to be fed to strix in a ltl-file file:

sweap/binaries/strix_tlsf_file.sh

Lines 35 to 38 in 76589ed

	truncate -s 0 ./ltl-file
	echo $LTL >> ./ltl-file
	strix --ins "$INS" --outs "$OUTS" --formula-file ./ltl-file ${OPTIONS[@]}

It would be cleaner if we used mktemp to create a fresh filename in the system's temporary directory. I still don't know if multiple instances of Sweap can run concurrently, but this would be a step in the right direction.