editor.foldingImportsByDefault shifts code around when you first open a file

[mjbvz]

Issue Type: Bug

1. With editor.foldingImportsByDefault disabled
2. Open a file with lots of imports and scroll down in the file
3. Put the file into a background tab
4. Enable editor.foldingImportsByDefault
5. Open the file again

Bug
The editor contents shift up when the imports are collapsed

VS Code version: Code - Insiders 1.59.0-insider (Universal) (818c661, 2021-07-21T05:15:01.788Z)
OS version: Darwin x64 20.5.0
Restricted Mode: No

System Info

Item	Value
CPUs	Intel(R) Core(TM) i9-9980HK CPU @ 2.40GHz (16 x 2400)
GPU Status	2d_canvas: enabled gpu_compositing: enabled metal: disabled_off multiple_raster_threads: enabled_on oop_rasterization: enabled opengl: enabled_on rasterization: enabled skia_renderer: disabled_off_ok video_decode: enabled webgl: enabled webgl2: enabled
Load (avg)	2, 2, 2
Memory (System)	32.00GB (0.07GB free)
Process Argv	--crash-reporter-id 48781ca2-1705-4f64-9bab-325055aab55d
Screen Reader	no
VM	0%

[aeschli]

Hope the fix does it. Sorry, didn't had much time to test and polish before leaving for vacation.