Include gdc.test prefix in test names (PR testsuite/88041)

Include gdc.test prefix in test names (PR testsuite/88041)

	PR testsuite/88041
	* lib/gdc-dg.exp (gdc-dg-test): Strip gdc.test prefix.
	* gdc.test/gdc-test.exp (gdc-do-test): Create $subdir link.
	Include $subdir in filename.
	Cleanup generated source.
	* gdc.test/compilable/ddoc9676a.d (EXTRA_SOURCES): Don't use
	absolute path.
	* gdc.test/compilable/depsOutput9948.d: Likewise.

From-SVN: r267094