fix: yarn install failed when dependency package using yarn in postin…

[benny1213]

What's the problem this PR addresses?

when running yarn install script, there is an error occur: "xx must be built because it never has been before or the last one failed" and the postinstall script of the error package did not run correctly.

Preconditions:

1. using yarnPath with a pre-built yarn.js
2. some of our npm package include yarn command in the postinstall script.

you can find more detail from minimal reproducible repo

How did you fix it?

after debug, i found the linkersCustomData did not restore correctly when running the yarn in the postinstall script, which causing yarn command in postinstall script refused to run.

so i tried calling project.restoreInstallState() when customData is missing to try restore the customData.

after i fixed this issue, i found two little issue still showing:

1. when calling project.findLocatorForLocation yarn alway pass a path with a / ending, but the locatorByPath map only contains key without / ending.
2. the locator should be a Locator struct instead of a string

i also fixed these two problem as the file changes show.

Checklist

• [x] I have read the Contributing Guide.

• [x] I have set the packages that need to be released for my changes to be effective.

• [x] I will check that all automated PR checks pass before the PR gets reviewed.