Fix remote EH environment after reconnection

For microsoft/vscode-remote-release#16

src/vs/workbench/api/node/extHostExtensionService.ts

@@ -758,6 +758,20 @@ export class ExtHostExtensionService implements ExtHostExtensionServiceShape {
 		return buff;
 	}
 
+	public async $setRemoteEnvironment(env: { [key: string]: string | null }): Promise<void> {
+		if (!this._initData.remote.isRemote) {
+			return;
+		}
+
+		for (const key in env) {
+			const value = env[key];
+			if (value === null) {
+				delete process.env[key];
+			} else {
+				process.env[key] = value;
+			}
+		}
+	}
 }
 
 function loadCommonJSModule<T>(logService: ILogService, modulePath: string, activationTimesBuilder: ExtensionActivationTimesBuilder): Promise<T> {