Update test viewlet to use codicon

[miguelsolorio]

vscode/src/vs/workbench/api/browser/viewsExtensionPoint.ts

Line 258 in 87287d0

const icon = URI.parse(require.toUrl('./media/test.svg'));

This should use our codicon via ThemeIcon. I attempted to update this but didn't have success as it impacted other parameters.

[sandy081]

Which codicon shall be used?

[miguelsolorio]

We have that icon as beaker in codicons:

[bpasero]

@sandy081 can you also delete the svg icon?