Improved consistency in test scripts.

2013-03-28  Jeremy Bennett <jeremy.bennett@embecosm.com>

	* run-tests.sh, run-elf32-tests.sh, run-uclibc-tests.sh: Replace
	ARC_TEST_TARGET with ARC_TEST_ADDR_ELF32 and ARC_TEST_ADDR_UCLIBC
	throughout. Add ARC_TEST_BOARD_ELF32 and ARC_TEST_BOARD_UCLIBC
	environment variables.