Merge from vscode 3c6f6af7347d38e87bc6406024e8dcf9e9bce229 (#8962)

* Merge from vscode 3c6f6af7347d38e87bc6406024e8dcf9e9bce229

* skip failing tests

* update mac build image

src/vs/workbench/api/common/cache.ts

@@ -0,0 +1,39 @@
+/*---------------------------------------------------------------------------------------------
+ *  Copyright (c) Microsoft Corporation. All rights reserved.
+ *  Licensed under the Source EULA. See License.txt in the project root for license information.
+ *--------------------------------------------------------------------------------------------*/
+
+export class Cache<T> {
+
+	private static readonly enableDebugLogging = false;
+
+	private readonly _data = new Map<number, readonly T[]>();
+	private _idPool = 1;
+
+	constructor(
+		private readonly id: string
+	) { }
+
+	add(item: readonly T[]): number {
+		const id = this._idPool++;
+		this._data.set(id, item);
+		this.logDebugInfo();
+		return id;
+	}
+
+	get(pid: number, id: number): T | undefined {
+		return this._data.has(pid) ? this._data.get(pid)![id] : undefined;
+	}
+
+	delete(id: number) {
+		this._data.delete(id);
+		this.logDebugInfo();
+	}
+
+	private logDebugInfo() {
+		if (!Cache.enableDebugLogging) {
+			return;
+		}
+		console.log(`${this.id} cache size — ${this._data.size}`);
+	}
+}