testsuite/gdc.test: Merge upstream dmd 5dd3eccc3

testsuite/gdc.test: Merge upstream dmd 5dd3eccc3

The D2 testsuite script has been updated to handle EXTRA_SOURCES and
EXTRA_FILES settings being split across multiple lines, which is how
they appear in upstream.

Reviewed-on: https://github.com/dlang/dmd/pull/9517

gcc/testsuite/ChangeLog:

2019-03-30  Iain Buclaw  <ibuclaw@gdcproject.org>

	* gdc.test/gdc-test.exp (gdc-copy-extra): Append copied files to
	cleanup_extra_files.
	(dmd2dg): Copy additional files after test is processed.
	(gdc-do-test): Remove all copied files after test.

From-SVN: r270038