kbuild breaks with FAIL, while it is infrastructure issue and must be ERROR

[nuclearcat]

Example:

+ cd /tmp/kci
+ wget -c -t 10 --retry-on-host-error https://files.kernelci.org/linux-next-master-next-20250530.tar.gz -O linux.tgz
--2025-05-30 06:49:22--  https://files.kernelci.org/linux-next-master-next-20250530.tar.gz
Resolving files.kernelci.org (files.kernelci.org)... 20.171.243.82
Connecting to files.kernelci.org (files.kernelci.org)|20.171.243.82|:443... connected.
HTTP request sent, awaiting response... 200 OK
Length: 0 [application/gzip]
Saving to: ‘linux.tgz’

     0K                                                        0.00 =0s

2025-05-30 06:49:25 (0.00 B/s) - ‘linux.tgz’ saved [0/0]

+ tar -xzf linux.tgz -C /tmp/kci/linux --strip-components=1

gzip: stdin: unexpected end of file
tar: Child returned status 1
tar: Error is not recoverable: exiting now

https://api.kernelci.org/viewer?node_id=683954e2a463751be4f25d23

Separate issue that this is rarly happening kernelci-storage failure, when it return size of file 0 bytes, i need to investigate it more.

Following things should be done:

• Try to autorecover on such error, maybe more complex strategy than just wget retries, also trigger if file is 0 bytes.
• Mark errors that happen NOT during builds as infrastructure error
• Fix kernelci-storage issue (race condition?)

[nuclearcat]

Fix: #2891