test: fix '-f' force option usage with test driver script (#3275)

Normally running '.ci/scripts/test.sh -b rc 18' -- to run tests against
a node v18 RC build -- would skip out because the latest RC build is for
a version that has an actual release. The '-f' flag exists to allow
still testing with that RC, which can be useful for dev work.

At some point this was busted, `NODE_FULL_VERSION` wouldn't be set and
a build step in ".ci/docker/node-edge-container/Dockerfile" would fail
(the `nvm install $NODE_FULL_VERSION`).

Author: trentm

.ci/scripts/test.sh

@@ -140,7 +140,7 @@ set -o xtrace
 
 # ---- For nightly and rc builds, determine if there is a point in testing.
 
-if [[ $BUILD_TYPE != "release" && $FORCE != "true" ]]; then
+if [[ $BUILD_TYPE != "release" ]]; then
   # If there is no nightly/rc build for this version, then skip.
   #
   # Note: We are relying on new releases being added to the top of index.tab,
@@ -165,7 +165,7 @@ if [[ $BUILD_TYPE != "release" && $FORCE != "true" ]]; then
   possible_release_version=${edge_node_version%-*}  # remove "-*" suffix
   release_version=$(curl -sS https://nodejs.org/dist/index.tab \
     | (grep -E "^${possible_release_version}\>" || true) | awk '{print $1}')
-  if [[ -n "$release_version" ]]; then
+  if [[ -n "$release_version" && $FORCE != "true" ]]; then
     skip "There is already a release build (${release_version}) of the latest v${NODE_VERSION} ${BUILD_TYPE} (${edge_node_version}). Skipping tests."
   fi