test-all.sh: always build with a fresh environment

scripts/test-all.sh

@@ -135,6 +135,9 @@ bake_all () {
     while [ $i -lt $array_length ]; do
 	activity="$txt_file_pkg_checking_kw $((i+1))/$array_length: ${array[$i]}"
 	echo $activity
+        # create clean bitbake environment
+	rm bitbake.lock cache/ sstate-cache/ tmp-eglibc/ -rf
+        bitbake
 	if [ "$arg" = "txt" ]; then
 	    # Try to bake every recipe. Store results in a report file. Just give $txt_file_pkg_ok_kw for working recipes, print more information on errors.
 	    echo $activity | tee -a "$report_file_raw" >> "$report_file_txt"