arc: Add new linker emulation and scripts for ARCv3 ISA.

Add ARCv3's linker bits. Remove obsolete tests.

ld/
xxxx-xx-xx  Claudiu Zissulescu  <claziss@synopsys.com>

	* ld/Makefile.am: Add ARC64 targets.
	* ld/configure.tgt: Likewise.
	* ld/Makefile.in: Regenerate.
	* ld/emulparams/arc64elf32.sh: New file.
	* ld/emulparams/arc64elf64.sh: Likewise.
	* ld/emulparams/arc64linux32.sh: Likewise.
	* ld/emulparams/arc64linux64.sh: Likewise.
	* ld/scripttempl/elfarc.sc: Update stack and heap definitions.
	* ld/testsuite/ld-arc/got-weak.d: Deleted file.
	* ld/testsuite/ld-arc/got-weak.s: Likewise.

Signed-off-by: Claudiu Zissulescu <claziss@synopsys.com>