Skip Docker tests for Windows stacks in integration suite

Windows containers cannot run on Linux Docker hosts used in CI.
This change makes the integration script exit gracefully when Docker
platform is requested with a Windows stack, similar to how the HWC
buildpack handles this scenario.

Author: ramonskie

scripts/integration.sh

@@ -72,6 +72,11 @@ function main() {
     if [[ "$(jq -r -S .integration.harness "${ROOTDIR}/config.json")" != "switchblade" ]]; then
       util::print::warn "NOTICE: This integration suite does not support Docker."
     fi
+    if [[ "${stack}" =~ ^windows ]]; then
+      util::print::warn "NOTICE: This integration suite does not support Docker on Windows stacks."
+      util::print::info "Windows containers cannot run on Linux Docker hosts. Use CF platform for Windows testing."
+      exit 0
+    fi
   fi
 
   declare -a matrix