compartment-mapper build fails with pnpm

[turadg]

Describe the bug

I tried out Yarn’s pnpm-linker in #2327
It’s failing at,

lerna ERR! yarn run build exited 1 in '@endo/test262-runner'
lerna ERR! yarn run build stderr:
Error running main: Error: Cannot find dependency eshost for file:///home/runner/work/endo/endo/packages/test262-runner/node_modules/test262-harness/
    at gatherDependency (file:///home/runner/work/endo/endo/packages/compartment-mapper/src/node-modules.js:485:11)

I thought it might be a missing dependency declaration, but the lockfile shows

"test262-harness@npm:^10.0.0":
  version: 10.0.0
  resolution: "test262-harness@npm:10.0.0"
  dependencies:
    eshost: "npm:^9.0.0"
    minimatch: "npm:^3.0.4"
    rxjs: "npm:^6.4.0"
    test262-stream: "npm:^1.3.0"
    yargs: "npm:^13.2.2"

node_modules/test262-harness has no node_modules inside it. I take it gatherDependency is making some assumption that doesn't hold with pnpm-style linking

endo/packages/compartment-mapper/src/node-modules.js

Lines 137 to 144 in 96b0140

	/**
	* findPackage behaves as Node.js to find third-party modules by searching
	* parent to ancestor directories for a `node_modules` directory that contains
	* the name.
	* Node.js does not actually require these to be packages, but in practice,
	* these are the locations that pakcage managers drop a package so Node.js can
	* find it efficiently.
	*

Steps to reproduce

1. gh pr checkout 2327
2. yarn install
3. yarn build

Expected behavior

Builds

Platform environment

• MacOS