re PR testsuite/39807 (Reporting of testsuite failures are messed up when using -j)

	PR testsuite/39807
	* dg-extract-results.sh: Close open files and use >> instead of >
	to decrease number of concurrently open files from awk.  Avoid
	= at the beginning of a regexp and redirect to a file determined
	by curfile variable rather than concatenated strings to workaround
	Solaris nawk bug.

From-SVN: r146850