testimage: drop target_dumper, host_dumper, and monitor_dumper

The target_dumper code is basically broken. It has been reading binary files
over the text base serial communication and runs at every command failure which
makes no sense. Each run might overwrite files from the previous run and the
output appears corrupted due to confusion from the binary data.

It isn't possible to cherry-pick "testimage: Drop target_dumper and most of monitor_dumper"
from master, so just make target_dumper, host_dumper, and monitor_dumper empty
functions.

For further details see:

https://lists.openembedded.org/g/openembedded-architecture/message/1888

(From OE-Core rev: 960e7e3dffa22c2142cb672c68cd9a8f0e3998a3)

Signed-off-by: Steve Sakoman <steve@sakoman.com>

meta/classes/testimage.bbclass

@@ -101,36 +101,12 @@ TESTIMAGE_DUMP_DIR ?= "${LOG_DIR}/runtime-hostdump/"
 TESTIMAGE_UPDATE_VARS ?= "DL_DIR WORKDIR DEPLOY_DIR"
 
 testimage_dump_target () {
-    top -bn1
-    ps
-    free
-    df
-    # The next command will export the default gateway IP
-    export DEFAULT_GATEWAY=$(ip route | awk '/default/ { print $3}')
-    ping -c3 $DEFAULT_GATEWAY
-    dmesg
-    netstat -an
-    ip address
-    # Next command will dump logs from /var/log/
-    find /var/log/ -type f -name !wtmp* 2>/dev/null -exec echo "====================" \; -exec echo {} \; -exec echo "====================" \; -exec cat {} \; -exec echo "" \;
 }
 
 testimage_dump_host () {
-    top -bn1
-    iostat -x -z -N -d -p ALL 20 2
-    ps -ef
-    free
-    df
-    memstat
-    dmesg
-    ip -s link
-    netstat -an
 }
 
 testimage_dump_monitor () {
-    query-status
-    query-block
-    dump-guest-memory {"paging":false,"protocol":"file:%s.img"}
 }
 
 python do_testimage() {