Fixes #60524

These properties are not inherited

Part of #60565

Adds a new `tsconfig.strictNullChecks.json` project that does not emit anything and is only used for enabling strict null checks on a subset of the vscode codebase.

Opt `iterator.ts` into strict null checking.

Fix our build scripts to properly handle `extends`

Fixes #59379

This reverts commit bab47f0f.

fixes #60444

fixes #60018

Tree Shaking:
- do not proceed with tree shaking when there are compilation errors
- load .d.ts files in the language service
- adopt TS 3.1.1 in symbol resolution
- use the real tsconfig.json / with "node" resolution

Bundling:
- fix issue where files were being looked for in out-build instead of out-editor-build

Fixes #60310

fixes #19003

* restructure menubar data to shrink cache

* remove old menu

* avoid storing common defaults for enabled, checked, and isNative

* remove old cache data for menubar/keybindings

Add throwable to php try/catch block snippet

Fixes #60291

Add setting to allow to disable Replace Preview

Prev/Next Panel/Sidebar view. Part of #44625