Remove all occurrences of 'mem2array' and 'array2mem'

Replace deprecated commands 'mem2array' and 'array2mem' with
new Tcl commands 'read_memory' and 'write_memory'.

Change-Id: I116d995995396133ca782b14cce02bd1ab917a4e
Signed-off-by: Marc Schink <dev@zapb.de>
Reviewed-on: https://review.openocd.org/c/openocd/+/6859
Tested-by: jenkins
Reviewed-by: Antonio Borneo <borneo.antonio@gmail.com>

testing/examples/cortex/cm3-ftest.cfg

@@ -50,7 +50,7 @@ proc load_and_run { name halfwords n_instr } {
 	echo "# code to trigger $name vector"
 	set addr 0x20000000
 
-	# array2mem should be faster, though we'd need to
+	# write_memory should be faster, though we'd need to
 	# compute the resulting $addr ourselves
 	foreach opcode $halfwords {
 		mwh $addr $opcode