Fix regression in renode container

- tagging to previous 1.15 version since 1.16 seems broken
- Enforcing nrf52 config set/restore for renode runs

Author: danielinux

tools/renode/Dockerfile

@@ -1,4 +1,4 @@
-FROM antmicro/renode:latest
+FROM docker.io/antmicro/renode:1.15.3
 
 RUN whoami
 USER root

tools/scripts/renode-test-update.sh

@@ -3,22 +3,42 @@
 export RENODE_UART=/tmp/wolfboot.uart
 export RENODE_PIDFILE=/tmp/renode.pid
 export RENODE_CONFIG=tools/renode/nrf52840_wolfboot.resc
+export RENODE_BUILD_CONFIG=config/examples/nrf52840.config
 export POFF=262139
 export RENODE_PORT=55155
 export RENODE_OPTIONS="--pid-file=$RENODE_PIDFILE --disable-xwt -P $RENODE_PORT"
 export EXPVER=tools/test-expect-version/test-expect-version
 export TEST_OPTIONS=$@
 
+RENODE_CONFIG_BACKUP=
+
+restore_build_config() {
+    if [ -n "$RENODE_CONFIG_BACKUP" ] && [ -f "$RENODE_CONFIG_BACKUP" ]; then
+        mv "$RENODE_CONFIG_BACKUP" .config
+    else
+        rm -f .config
+    fi
+}
+
+prepare_build_config() {
+    if [ -f .config ]; then
+        RENODE_CONFIG_BACKUP=$(mktemp /tmp/wolfboot-renode-config.XXXXXX)
+        cp .config "$RENODE_CONFIG_BACKUP"
+    fi
+    cp "$RENODE_BUILD_CONFIG" .config
+}
+
 quit_renode() {
     if (which nc); then
         (echo && echo quit && echo) | nc -q 1 localhost $RENODE_PORT >/dev/null
     fi
 }
 
-
+trap restore_build_config EXIT
 
 
 rm -f $RENODE_UART
+prepare_build_config
 
 make keysclean
 make keytools