[fuchsia] Update checkout_fuchsia_boot_images

We follow Chromium and only download the image qemu.x64

Change-Id: I13e06c5646e889af2acfac8c8e9cb971a7a36c56
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3858299
Auto-Submit: Victor Gomes <victorgomes@chromium.org>
Commit-Queue: Victor Gomes <victorgomes@chromium.org>
Reviewed-by: Michael Achenbach <machenbach@chromium.org>
Commit-Queue: Michael Achenbach <machenbach@chromium.org>
Cr-Commit-Position: refs/heads/main@{#82791}

DEPS

@@ -12,17 +12,20 @@ vars = {
   # Fetches only the SDK boot images which match at least one of the whitelist
   # entries in a comma-separated list.
   #
-  # Only the X64 and ARM64 QEMU images are downloaded by default. Developers
-  # that need to boot on other target architectures or devices can opt to
-  # download more boot images. Example of images include:
+  # Available images:
+  #   Emulation:
+  #   - qemu.x64 (pulls terminal.qemu-x64-release)
+  #   - qemu.arm64 (pulls terminal.qemu-arm64-release)
+  #   - workstation.qemu-x64-release
+  #   Hardware:
+  #   - generic.x64 (pulls terminal.x64-debug)
+  #   - generic.arm64 (pulls terminal.arm64-debug)
+  #   - chromebook.x64 (pulls terminal.chromebook-x64-debug)
   #
-  # Emulation:
-  #   qemu.x64, qemu.arm64
-  # Hardware:
-  #   generic.x64, generic.arm64
-  #
-  # Wildcards are supported (e.g. "qemu.*").
-  'checkout_fuchsia_boot_images': "qemu.x64,qemu.arm64",
+  # Since the images are hundreds of MB, default to only downloading the image
+  # most commonly useful for developers. Bots and developers that need to use
+  # other images (e.g., qemu.arm64) can override this with additional images.
+  'checkout_fuchsia_boot_images': "qemu.x64",
 
   'checkout_instrumented_libraries': False,
   'checkout_ittapi': False,