MIPS/GAS/testsuite: Convert ISA override list tests to dump tests

MIPS/GAS/testsuite: Convert ISA override list tests to dump tests

And remove the zillion duplicate sources.  Also `mips1@isa-override-2.l'
is the same as `r3000@isa-override-2.l', so remove the latter too, now
that `r3000@isa-override-2.d' can name a file to match stderr output
against.

	gas/
	* testsuite/gas/mips/isa-override-2.d: New test.
	* testsuite/gas/mips/mips1@isa-override-2.d: New test.
	* testsuite/gas/mips/r3000@isa-override-2.d: New test.
	* testsuite/gas/mips/r3900@isa-override-2.d: New test.
	* testsuite/gas/mips/mips2@isa-override-2.d: New test.
	* testsuite/gas/mips/mips32@isa-override-2.d: New test.
	* testsuite/gas/mips/mips32r2@isa-override-2.d: New test.
	* testsuite/gas/mips/mips32r3@isa-override-2.d: New test.
	* testsuite/gas/mips/mips32r5@isa-override-2.d: New test.
	* testsuite/gas/mips/mips32r6@isa-override-2.d: New test.
	* testsuite/gas/mips/octeon3@isa-override-2.d: New test.
	* testsuite/gas/mips/r3000@isa-override-2.l: Remove list test.
	* testsuite/gas/mips/mips1@isa-override-2.s: Remove test source.
	* testsuite/gas/mips/r3000@isa-override-2.s: Remove test source.
	* testsuite/gas/mips/r3900@isa-override-2.s: Remove test source.
	* testsuite/gas/mips/mips2@isa-override-2.s: Remove test source.
	* testsuite/gas/mips/mips32@isa-override-2.s: Remove test
	source.
	* testsuite/gas/mips/mips32r2@isa-override-2.s: Remove test
	source.
	* testsuite/gas/mips/mips32r3@isa-override-2.s: Remove test
	source.
	* testsuite/gas/mips/mips32r5@isa-override-2.s: Remove test
	source.
	* testsuite/gas/mips/mips32r6@isa-override-2.s: Remove test
	source.
	* testsuite/gas/mips/octeon3@isa-override-2.s: Remove test
	source.
	* gas/testsuite/gas/mips/mips.exp: Fold corresponding list tests
	into the new tests.