verifier: allow inferred Windows platform versions

[crazy-max]

This relates to docker/buildx#4008. When testing that change with docker buildx --builder builder bake https://github.com/docker/buildkit-syft-scanner.git image-all, the verifier reports that the requested platforms include windows/amd64 while the result platforms include windows(10.0.26100.33296)/amd64:

docker buildx --builder builder bake https://github.com/docker/buildkit-syft-scanner.git image-all
...
#34 Verifying build result
#34 WARN: Requested platforms linux/amd64,linux/arm/v7,linux/arm64,linux/ppc64le,linux/riscv64,linux/s390x,windows/amd64 do not match result platforms linux/amd64,linux/arm/v7,linux/arm64,linux/ppc64le,linux/riscv64,linux/s390x,windows(10.0.26100.33296)/amd64
#34 DONE 0.0s
WARNING: No output specified for image-all target(s) with docker-container driver. Build result will only remain in the build cache. To push result image into registry use --push or to load image into docker use --load

 1 warning found (use docker --debug to expand):
 - Requested platforms linux/amd64,linux/arm/v7,linux/arm64,linux/ppc64le,linux/riscv64,linux/s390x,windows/amd64 do not match result platforms linux/amd64,linux/arm/v7,linux/arm64,linux/ppc64le,linux/riscv64,linux/s390x,windows(10.0.26100.33296)/amd64

View build details: docker-desktop://dashboard/build/builder/builder0/9xvawy2lahqip1mjngno84byi

The Dockerfile frontend may infer a concrete Windows OS version from the base image even when the request used versionless windows/amd64. The verifier already tolerated this for single-platform builds, but multi-platform builds still compared the requested and result platform sets strictly and emitted a mismatch warning.

This updates the multi-platform verifier path to use strict platform matching for result platforms that don't match by exact FormatAll key. This keeps explicit Windows OS version requests strict, while allowing the existing inferred Windows OS version behavior to pass without warning.