Multi-select with keyboard misses the initial cell

[kieferrm]

Issue Type: Bug

1. Select a cell
2. Shift Arrow Down to select 3 more cells
   The first time you end up with 4 selected cells.
3. ESC to get rid of the selection
4. Arrow up to the cell from 1)
5. Repeat step 2)
   -> only three cells are selected, the first one is left out

VS Code version: Code - Insiders 1.55.0-insider (Universal) (5d80c30, 2021-03-08T05:24:34.127Z)
OS version: Darwin arm64 20.3.0
Remote OS version: Linux x64 5.4.0-1031-azure
Remote OS version: Linux x64 5.4.0-1036-azure
Remote OS version: Linux x64 5.4.0-1031-azure

System Info

Item	Value
CPUs	undefined
GPU Status	2d_canvas: enabled gpu_compositing: enabled metal: disabled_off multiple_raster_threads: enabled_on oop_rasterization: enabled opengl: enabled_on protected_video_decode: unavailable_off rasterization: enabled skia_renderer: disabled_off_ok video_decode: enabled webgl: enabled webgl2: enabled
Load (avg)	2, 2, 2
Memory (System)	16.00GB (0.11GB free)
Process Argv	--enable-proposed-api lszomoru.lszomoru-proposed-api-sample --crash-reporter-id ef10dfea-3602-4c74-ba1a-109ce7da7825
Screen Reader	no
VM	0%

Item	Value
Remote	SSH: az-devbox
OS	Linux x64 5.4.0-1031-azure
CPUs	Intel(R) Xeon(R) CPU E5-2673 v4 @ 2.30GHz (4 x 2294)
Memory (System)	15.64GB (5.93GB free)
VM	0%

Item	Value
Remote	Codespaces
OS	Linux x64 5.4.0-1036-azure
CPUs	Intel(R) Xeon(R) Platinum 8168 CPU @ 2.70GHz (8 x 2693)
Memory (System)	15.64GB (7.89GB free)
VM	0%

Item	Value
Remote	SSH: az-devbox
OS	Linux x64 5.4.0-1031-azure
CPUs	Intel(R) Xeon(R) CPU E5-2673 v4 @ 2.30GHz (4 x 2294)
Memory (System)	15.64GB (5.93GB free)
VM	0%

Extensions (52)

Extension	Author (truncated)	Version
tsl-problem-matcher	eam	0.4.0
vsc-material-theme	Equ	33.1.2
vsc-material-theme-icons	equ	1.2.2
codespaces	Git	0.8.1
Kotlin	mat	1.7.1
theme-monokai-pro-vscode	mon	1.1.18
remote-ssh-edit-nightly	ms-	2021.3.12420
remote-ssh-nightly	ms-	2021.3.12420
remote-wsl	ms-	0.54.2
azure-account	ms-	0.9.7
github-browser	ms-	0.0.15
vscode-github-issue-notebooks	ms-	0.0.70
material-icon-theme	PKi	4.5.0
vscode-ruby	win	0.28.0
vscode-track-build-errors	aes	0.0.3
git-branch	ale	1.7.0
github-markdown-preview	bie	0.0.2
markdown-checkbox	bie	0.1.3
markdown-emoji	bie	0.1.0
markdown-preview-github-styles	bie	0.1.6
markdown-yaml-preamble	bie	0.0.4
vscode-svgviewer	css	2.0.0
vscode-eslint	dba	2.1.16
typescript-notebook	don	1.1.0
gitlens	eam	11.3.0
tsl-problem-matcher	eam	0.4.0
vsc-material-theme	Equ	33.1.2
vsc-material-theme-icons	equ	1.2.2
graphviz-markdown-preview	gee	0.0.8
codespaces	Git	0.8.1
vscode-pull-request-github	Git	0.24.0
vscode-pull-request-github-insiders	Git	2021.3.12063
mdmath	goe	2.5.1
lszomoru-proposed-api-sample	lsz	0.0.1
Kotlin	mat	1.7.1
rainbow-csv	mec	1.8.1
theme-monokai-pro-vscode	mon	1.1.18
vscode-docker	ms-	1.10.0
python	ms-	2021.2.636928669
jupyter	ms-	2021.4.625511240
azure-account	ms-	0.9.7
azurecli	ms-	0.5.0
hexeditor	ms-	1.4.0
js-debug-nightly	ms-	2021.3.817
vscode-github-issue-notebooks	ms-	0.0.70
vscode-js-profile-flame	ms-	0.0.14
vscode-markdown-notebook	ms-	0.0.14
material-icon-theme	PKi	4.5.0
ruby	reb	0.28.1
vscode-xml	red	0.15.0
code-spell-checker	str	1.10.2
vscode-ruby	win	0.28.0

(9 theme extensions excluded)

A/B Experiments

vsliv695:30137379
vsins829:30139715
vsliv368:30146709
vsreu685:30147344
python383:30185418
pythonvspyt602:30263608
vspor879:30202332
vspor708:30202333
vspor363:30204092
vstry244:30244315
pythonvsdeb440:30224570
pythonvsded773:30223139
pythonvspyt875:30259475
pythonvsnew554:30265444
pythontb:30258533
openwslfolder:30268768
vscoresta800:30265947
vspre833:30267464

[rebornix]

This bug can go away once we have #118045 and #118482 but I'll also see a fix for current arch.

[rebornix]

Fixed via #118045