Fuzzy finder: filenames are slow to re-download and re-index within a single SPA session

Created by: olafurpg

• Sourcegraph version: latest live version
• Platform information: website

Steps to reproduce:

1. Open Chromium repo https://sourcegraph.com/github.com/chromium/chromium/-/blob/third_party/android_deps/libs/org_ow2_asm_asm/OWNERS
2. Trigger fuzzy finder with shortcut Cmd+P
3. Open a random file
4. Repeat step 2, the files get re-downloaded and re-indexed, which is slow

Expected behavior:

Step 4 should feel instant because the files should already be cached.

Actual behavior:

Step 4 is slow.