Use the new Testing API to show coverage counts for files and "Run With Coverage" button

[dundee]

Is your feature request related to a problem? Please describe.

VSCode 1.88 comes with new testing API .
New button for "Run With Coverage" can be added and also a new box with visual representation of coverage of individual files was added.

Describe the solution you'd like
Go extension should add the "Run With Coverage" button and box for coverage counts.

Additional context

[adonovan]

Related:

• x/tools/gopls: integrate test discovery go#59445
• Cannot run nested tests over more than 2 levels #3022
• GoTestResolver: Limit scope of indexing to the package level instead of entire workspace/module #2504