Release testing instructions: Storefront 3.9.0

Avoid text in buttons breaking in the middle of words (#1797)

1. Install and activate all the required plugins.
2. Complete the onboarding setup wizard.
3. Choose the Storefront theme.
4. Add Some Products.
5. Go to Appearance->Customize.
6. Select WooCommerce->Product catalog option.
7. Set product per rows value to 6.
8. Observe that "Add to Cart" button text now does not appear misaligned.

Update WooCommerce default color (#1769)

1. Go to /wp-admin/customize.php » Typography » Link/accent color
2. Ensure that the default color code is #7f54b3.