Storing cache in globalState is causing slow startup

[Tony]

Describe the bug

We're storing icon cache in globalState, and it will be saved to globalStorage/state.vscdb which gets loaded in every startup even after uninstall

I discovered this when trying to troubleshoot why my vscode is starting slowly recently, and found something related in loading storage in perfview.show, and saw this big cache entry in it, removing it solves the problem

Reproduction

Try use some icons and use perfview.show to see code/didInitStorage's delta time

System Info

* Code: 1.79.2 (695af097c7bd098fbf017ce3ac85e09bbc5dda06)
* OS: win32(10.0.19045)
* CPUs: 11th Gen Intel(R) Core(TM) i5-11400 @ 2.60GHz(12 x 2592)
* Memory(System): 15.83 GB(6.97GB free)

- 1TB M.2 SSD

Used Package Manager

n/a

Validations

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• The provided reproduction is a minimal reproducible of the bug.

[Anthony Fu]

PR welcome if you have better solutions. Thanks

[Tony]

I'll take a look, maybe using the way how built-in json language features extension store schema caches