Add last modify field "mtime" for FileBlob (#1431)

[zhongweiy]

mtime value is epoch time stamp in millisecond unit.

[Jarred-Sumner]

Thank you for this. To match Web APIs, the property will need to be named lastModified instead of mtime but otherwise this is pretty close to mergeable.

Some unrelated tests will fail, don’t worry about those because we haven’t finished getting CI to be green yet (recently added more test coverage)

[zhongweiy]

Jarred, thanks for your review. Make sense to me and the commit is updated.

[Jarred-Sumner]

macOS build is failing: https://github.com/oven-sh/bun/actions/runs/4534479006/jobs/8018213230?pr=2491

store.data.file.last_modified = toJSTime(stat.mtim.tv_sec, stat.mtim.tv_nsec);

I think it needs to be stat.mtime

[Jarred-Sumner]

Merging but we need to add the missing types to TypeScript