Fixes flaky tests in schedules.tests.TestCourseUpdateResolver

Description

Uses `CacheIsolationTestCase` to fix flaky tests added by https://github.com/edx/edx-platform/pull/19018

*JIRA tickets*: OSPR

*Discussions*: Please see https://github.com/edx/edx-platform/pull/19018#issuecomment-461482855

*Merge deadline*: ASAP

*Testing instructions*:

<HaltingProblem>
This is a fix to the automated tests only, so the tests passing (all the time) is the way to verify this works.
</HaltingProblem>

*Reviewers*

  • [ ] @jmbowman

CC @awaisdar001

Assignee

Jeremy Bowman

Reporter

Open Source Pull Request Bot

Contributor Name

Jillian Vogel

Repo

edx/edx-platform

Customer

Epic Link

None

OSCM Assignee

None

Platform Map Area (Levels 1 &amp; 2)

None

Platform Map Area (Levels 3 &amp; 4)

None

Blended Hour Utilization Percentage

None

Priority

Unset
Configure