CI: add Cache step for more runs

[marxin]

Plus, I removed setting the CARGO_ROOT_DIR, we should be fine caching only the default 2 locations, the same what rust-cache does: https://github.com/Swatinem/rust-cache?tab=readme-ov-file#cache-details.

[Copilot]

Pull request overview

This PR adds S3-based caching steps to several CI workflow jobs and removes the legacy Azure-based sccache configuration from multiple workflow files. The goal is to speed up CI runs by caching Rust build artifacts and dependencies.

• Added four new cache steps using whywaita/actions-cache-s3@v2 for jobs: test_nodejs, test_wasi_fyi, test_wasix, and test_build_jsc
• Removed SCCACHE_AZURE_BLOB_CONTAINER and SCCACHE_AZURE_CONNECTION_STRING environment variables from test.yaml, build.yml, and benchmark.yaml
• Minor whitespace cleanup (removed empty lines) in test.yaml

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 8 comments.

File	Description
.github/workflows/test.yaml	Added S3 cache steps to four jobs (test_nodejs, test_wasi_fyi, test_wasix, test_build_jsc) and removed sccache Azure env vars from three matrix jobs
.github/workflows/build.yml	Removed sccache Azure env vars and commented-out use_sccache parameter
.github/workflows/benchmark.yaml	Removed sccache Azure env vars

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