Replace deprecated tcl case statements with switch statements

Replace deprecated tcl case statements with switch statements

binutils/
	* testsuite/lib/binutils-common.exp (big_or_little_endian): Replace
	case statement with switch statement.
gas/
	* testsuite/gas/all/gas.exp: Replace case statements with switch
	statements.
	* testsuite/gas/elf/elf.exp: Likewise.
	* testsuite/gas/macros/macros.exp: Likewise.
	* testsuite/lib/gas-defs.exp: Likewise.
ld/
	* testsuite/ld-elfvers/vers.exp: Replace case statements with
	switch statements.
	* testsuite/ld-ifunc/ifunc.exp: Likewise.
	* testsuite/ld-unique/unique.exp: Likewise.