Tests: bsim: Use correct compilation folder

If a test was written outside 'app_root' the 'app' path may contain
previous directory ('..') which would lead to the compilation file being
written outside the 'WORK_DIR'.

Fix the issue by checking if the 'app' is inside 'app_root', if it's
not, use the absolute path to the app for creating the 'this_dir'
variable.

Signed-off-by: Théo Battrel <theo.battrel@nordicsemi.no>

tests/bsim/compile.source

@@ -42,6 +42,10 @@ function _compile(){
   local map_file_name=${exe_name}.Tsymbols
 
   local this_dir=${WORK_DIR}/${app}/${exe_basename}
+  local app_absolute=$(realpath "${app_root}/${app}")
+  if [[ "${app_absolute}" != "${app_root}"* ]]; then
+    this_dir=${WORK_DIR}/${app_absolute}/${exe_basename}
+  fi
 
   local modules_arg="${ZEPHYR_MODULES:+-DZEPHYR_MODULES=${ZEPHYR_MODULES}}"