fix service tests on windows; run [crates] (to prove service tests still run)

[chris48s]

Refs #8437

This doesn't fix the :trace variant but it does fix being able to run npm run test:services -- only="myservice" on Windows.

The core fix here is actually:

diff --git a/core/base-service/loader.js b/core/base-service/loader.js
index 9bbf0c948..5fd87cd87 100644
--- a/core/base-service/loader.js
+++ b/core/base-service/loader.js
@@ -103,7 +103,7 @@ async function collectDefinitions() {
 async function loadTesters() {
   return Promise.all(
     glob
-      .sync(path.join(serviceDir, '**', '*.tester.js'))
+      .sync(toUnixPath(path.join(serviceDir, '**', '*.tester.js')))
       .map(async path => await import(`file://${path}`))
   )
 }

(basically in #8350 we missed the tests loader).

My original plan was to do that and directly write tests for loadTesters() and loadServiceClasses() but loading all the tester classes with .map(async path => await import(`file://${path}`)) inside an expect() was causing some strange side effects with chai, so I decided to separate discovering all the files from loading them and write a test for just making sure we discover the files, which is why there is a bit more refactoring going on in this PR.

Side note: This doesn't have any bearing on anything, but I am unreasonably annoyed with myself, windows users, and the world as a whole that I had to install Windows in a VirtualBox in order to work this out when it basically amounted to applying a fix I had already worked out previously without having to do that.

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[calebcartwright]

LGTM. Might be worth setting up a recurring CI check with Actions too

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