SITES-49454: [Extensibility] Host issues affects RTE loading on CFE

[VladimirZaets]

Description

Related Issue

Motivation and Context

How Has This Been Tested?

Screenshots (if appropriate):

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

Checklist:

• I have signed the Adobe Open Source CLA.
• My code follows the code style of this project.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have read the CONTRIBUTING document.
• I have added tests to cover my changes.
• All new and existing tests passed.

[fe-lix-]

Opened #153, which supersedes this PR: same fix (cherry-picked, same commit/authorship), plus a regression test for the host-reuse-on-empty-to-non-empty-transition path that this PR's tests didn't cover. Details in the review comment above and in #153's description.