Support chain_id in loading multi-transaction state tests

[gumb0]

Also set default chain_id to 1 - see confirmation that this is expected behavior https://discord.com/channels/595666850260713488/753271902520213625/1280839101687533619

Pulled out of #961, required for 7702 tests.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 94.19%. Comparing base (bae4933) to head (7f2c594).

Additional details and impacted files

@@           Coverage Diff           @@
##           master    #1023   +/-   ##
=======================================
  Coverage   94.19%   94.19%           
=======================================
  Files         149      149           
  Lines       15887    15888    +1     
=======================================
+ Hits        14964    14965    +1     
  Misses        923      923           

Flag	Coverage Δ
eof_execution_spec_tests	17.24% <60.00%> (+<0.01%)	⬆️
ethereum_tests	27.33% <60.00%> (+<0.01%)	⬆️
ethereum_tests_silkpre	19.13% <40.00%> (+0.01%)	⬆️
execution_spec_tests	20.42% <60.00%> (+<0.01%)	⬆️
unittests	88.96% <100.00%> (+<0.01%)	⬆️

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Files with missing lines	Coverage Δ
test/statetest/statetest_loader.cpp	96.85% <100.00%> (+0.01%)	⬆️
test/unittests/statetest_loader_test.cpp	100.00% <100.00%> (ø)
test/unittests/statetest_loader_tx_test.cpp	100.00% <100.00%> (ø)