Add a dw2-3.S test

Add a dw2-3.S test

This patch adds a dw2-3.S test for upcoming SHF_COMPRESSED test. The
existing dw2-1.S/dw2-2.S tests generate non-compressed debug sections
for SHF_COMPRESSED since SHF_COMPRESSED compressed debug sections are
bigger.

	* binutils-all/compress.exp (testfile): Remove suffix.
	(compressedfile): Likewise.
	(compressedfile2): Likewise.
	(libfile): Likewise.
	(testfile3): New.
	(compressedfile3): Likewise.
	Updated.
	Add a dw2-3.S test.
	* binutils-all/dw2-3.S: New file.
	* binutils-all/dw2-3.W: Likewise.