Remove run_dump_test support for objcopy as a dump program

Remove run_dump_test support for objcopy as a dump program

We have three copies of run_dump_test in the testsuite.  This is a first
step towards consolidating them.

A few tests use objcopy to convert to verilog or srec output, then
check that output is as expected.  Those tests can just as easily use
objdump, keeping the set of dump programs (addr2line, nm, objdump,
readelf, size) separate from utilities under test.  That in turn makes
auto-detecting the dump program possible in more places.

binutils/
	* testsuite/binutils-all/group-7a.d,
	* testsuite/binutils-all/group-7b.d,
	* testsuite/binutils-all/group-7c.d,
	* testsuite/binutils-all/symbols-1.d,
	* testsuite/binutils-all/symbols-2.d,
	* testsuite/binutils-all/symbols-3.d,
	* testsuite/binutils-all/symbols-4.d: Remove DUMPPROG.
gas/
	* testsuite/gas/mri/char.d: Don't objcopy to srec, objdump instead.
	* testsuite/gas/mri/float.d: Likewise.
	* testsuite/lib/gas-defs.exp (run_dump_test): Remove support
	for objcopy as a dump tool.
ld/
	* testsuite/ld-elf/interleave-0.d,
	* testsuite/ld-elf/interleave-4.d: Don't objcopy to srec,
	objdump instead.
	* testsuite/ld-gc/all-debug-sections.d,
	* testsuite/ld-scripts/provide-4.d,
	* testsuite/ld-scripts/provide-5.d,
	* testsuite/ld-scripts/provide-6.d,
	* testsuite/ld-scripts/provide-7.d,
	* testsuite/ld-scripts/provide-8.d,
	* testsuite/ld-scripts/segment-start.d: Remove PROG, specify
	nm instead.
	* testsuite/lib/ld-lib.exp (run_dump_test): Remove support
	for objcopy as a dump tool.