Toggling terminal with experimental grid layout can get window into bad layout

[mjbvz]

Issue Type: Bug

Repo

1. Open window.
2. Toggle terminal with ctrl+`
3. Drag the terminal down to collapse it
4. Now toggle the terminal again

Bug

Possibly #68247 but I don't know what issue that is a duplicate of

VS Code version: Code - Insiders 1.32.0-insider (a509265, 2019-02-13T06:15:00.223Z)
OS version: Darwin x64 18.2.0

System Info

Item	Value
CPUs	Intel(R) Core(TM) i7-4770HQ CPU @ 2.20GHz (8 x 2200)
GPU Status	2d_canvas: enabled checker_imaging: disabled_off flash_3d: enabled flash_stage3d: enabled flash_stage3d_baseline: enabled gpu_compositing: enabled multiple_raster_threads: enabled_on native_gpu_memory_buffers: enabled rasterization: enabled surface_synchronization: enabled_on video_decode: enabled webgl: enabled webgl2: enabled
Load (avg)	3, 3, 3
Memory (System)	16.00GB (0.04GB free)
Process Argv	-psn_0_36041309
Screen Reader	no
VM	20%

Extensions (37)

Extension	Author (truncated)	Version
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emojisense	bie	0.4.1
folder-source-actions	bie	0.0.4
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lit-html	bie	1.11.0
markdown-checkbox	bie	0.1.1
markdown-emoji	bie	0.0.7
markdown-image-size	bie	0.0.2
markdown-mermaid	bie	1.1.2
speech	bie	0.0.2
dart-code	Dar	2.22.3
vscode-eslint	dba	1.8.0
gitlens	eam	9.5.0
vscode-npm-script	eg2	0.3.5
vscode-pull-request-github	Git	0.4.0
vscode-styled-components	jpo	0.0.25
vscode-memfs	jri	0.0.3
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vscode-sshfs	Kel	1.12.3
vscode-azurefunctions	ms-	0.14.0
vscode-cosmosdb	ms-	0.9.1
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vscode-language-pack-zh-hans	MS-	1.31.4
mssql	ms-	1.4.0
python	ms-	2019.1.0
azure-account	ms-	0.8.0
Go	ms-	0.9.2
vscode-typescript-tslint-plugin	ms-	1.0.0
vsliveshare	ms-	0.3.1182
debugger-for-chrome	msj	4.11.2
live-server-preview	neg	0.1.4
java	red	0.38.0
shader	sle	1.1.4
code-spell-checker	str	1.6.10
vscode-java-debug	vsc	0.16.0
vscode-java-dependency	vsc	0.3.0

(15 theme extensions excluded)