Move register backups extension dev check back to windows

EnvironmentService's config may be stale.

src/vs/code/electron-main/windows.ts

@@ -767,7 +767,9 @@ export class WindowsManager implements IWindowsMainService {
 			}
 		}
 
-		this.backupService.registerWindowForBackups(vscodeWindow.id, !configuration.workspacePath, emptyWorkspaceBackupFolder, configuration.workspacePath);
+		if (!configuration.extensionDevelopmentPath) {
+			this.backupService.registerWindowForBackups(vscodeWindow.id, !configuration.workspacePath, emptyWorkspaceBackupFolder, configuration.workspacePath);
+		}
 
 		// Only load when the window has not vetoed this
 		this.lifecycleService.unload(vscodeWindow, UnloadReason.LOAD).done(veto => {

src/vs/platform/backup/electron-main/backupMainService.ts

@@ -51,11 +51,6 @@ export class BackupMainService implements IBackupMainService {
 	}
 
 	public registerWindowForBackups(windowId: number, isEmptyWorkspace: boolean, backupFolder?: string, workspacePath?: string): void {
-		// Backups and hot exit are disabled during extension development
-		if (this.environmentService.isExtensionDevelopment) {
-			return;
-		}
-
 		// Generate a new folder if this is a new empty workspace
 		if (!backupFolder) {
 			backupFolder = Date.now().toString();