Background indexing is crushing CPU

[bbrk24]

Swift version

Reproduced on swift-6.1-RELEASE, swift-6.1.2-RELEASE, and swift-6.2-RELEASE

Platform

Reproduced on Windows 11 and Ubuntu 22.04

Editor

VS Code with the official extension

Description

Background indexing spawns more than twice as many swift-frontend processes as I have ncpu, leading to maxing out my CPU usage and causing system-wide lag (e.g. single-digit-fps mouse cursor movement). Attached is a screenshot of htop during background indexing.

Potentially related to #1837

Steps to Reproduce

Reproduced with swift-cross-ui

Logging

No response