fix error reporting of timeout when getting invalid response, switch build to go 1.22.2

[ldemailly]

Fixes #913 relies on fortio/log#60

Also bump go version in build image as 1.22.2 (and 1.21.9) were just released

tested using the bad server from #913 (comment)

and

go run . load -c 1 -n 2 localhost:3000

before

10:01:03.409 [ERR] Read error, err={"Op":"read","Net":"tcp","Source":{"IP":"127.0.0.1","Port":59061,"Zone":""},"Addr":{"IP":"127.0.0.1","Port":3000,"Zone":""},"Err":{}}, size=107, dest={"IP":"127.0.0.1","Port":3000,"Zone":""}, url="http://localhost:3000/foo", thread=0, run=0

after

12:56:28.318 r1 [ERR] http_client.go:1096> Timeout error (incomplete/invalid response), err="read tcp 127.0.0.1:63786->127.0.0.1:3000: i/o timeout", size=107, header_len=0, dest={"IP":"127.0.0.1","Port":3000,"Zone":""}, url="http://localhost:3000", thread=0, run=0

add header_len so it's easier to tell that CR+LF wasn't yet found and explicit message for timeout as well

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 88.8%. Comparing base (1a5a8ba) to head (6aa079b).

Additional details and impacted files

@@          Coverage Diff           @@
##           master    #914   +/-   ##
======================================
  Coverage    88.8%   88.8%           
======================================
  Files          17      17           
  Lines        5028    5034    +6     
======================================
+ Hits         4466    4472    +6     
  Misses        414     414           
  Partials      148     148           

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

[tejaspbajaj]

lgtm, thanks