moduleSpecifiers: Simpler criteria for preferring relative path vs baseUrl

[ghost]

Fixes microsoft/vscode#52485

Previously we were just checking if relativePath climbed all the way up to baseUrl. But in a case where we have /src/d0/d1/d2/d3/d4/d5/user.ts importing from src/d0/a.ts, it was only climbing up most of the way to baseUrl. pathFromSourceToBaseUrl grew just as fast as relativePath and we never switched over to using baseUrl.

New criteria is to just count the number of components in each path.

[mhegazy]

@weswigham this relevant to the discussion we had earlier about comparing "better-ness".

[weswigham]

Right, although in the context of declaration emit, the betterness of multiple non-relative specifiers are probably more important.

At least for declarations, I see the priority as probably module name > shortest node_modules absolute > other node_modules absolute > relative > base url absolute - the base url case moved to the end because declarations don't carry their baseUrl setting with them, so relying on it in declaration emit is liable to cause awkward names to crop up (like src/app when ../app would be better).

[ghost]

Latest commit fixes #26348