Use plain node instead of jsdom environment when testing jbrowse/img

package.json

@@ -18,7 +18,7 @@
     "check-format": "prettier --check .",
     "typecheck": "tsc --noEmit",
     "pretest-ci": "cd products/jbrowse-react-linear-genome-view;yarn build;cd ../../",
-    "test-ci": "cross-env NODE_OPTIONS='--max-old-space-size=7000' jest --ci --coverage && jest --testMatch '**/*testmod.js'",
+    "test-ci": "cross-env NODE_OPTIONS='--max-old-space-size=7000' jest --ci --coverage && jest --env node --testMatch '**/*testmod.js'",
     "built-test-ci": "jest --ci integration.test.js",
     "test": "jest"
   },

products/jbrowse-img/src/index.js

@@ -1,15 +1,17 @@
 /* eslint-disable no-console */
 import fs from 'fs'
 import yargs from 'yargs'
-import jsdom from 'jsdom'
 import { standardizeArgv, parseArgv } from './parseArgv'
 import { renderRegion } from './renderRegion'
 import tmp from 'tmp'
 import 'abortcontroller-polyfill/dist/abortcontroller-polyfill-only'
 import { spawnSync } from 'child_process'
 import fetch, { Headers, Response, Request } from 'node-fetch'
+import { JSDOM } from 'jsdom'
+
+const { document } = new JSDOM(`...`).window
+global.document = document
 
-global.document = jsdom.jsdom()
 if (!global.fetch) {
   global.fetch = fetch
   global.Headers = Headers

products/jbrowse-img/src/index.testmod.js

@@ -1,5 +1,10 @@
 import { renderRegion } from './renderRegion'
 import fs from 'fs'
+import { JSDOM } from 'jsdom'
+import 'abortcontroller-polyfill/dist/abortcontroller-polyfill-only'
+
+const { document } = new JSDOM(`...`).window
+global.document = document
 
 function hashCode(str) {
   let hash = 0