Require MAX_INITCODE_SIZE limit to be satisfied during validation

[pdobacz]

Pushing in form of a PR after discussion during EOF implementers call 49.

To reiterate the reasoning behind:

Synopsis of the problem:

• subcontainer have size limit of 64K implied by the header format
• but this doesn't apply to "top-level" containers!
• we have EIP-3860 MAX_INITCODE_SIZE of 48K - but not part of EOF validation!
• EVM implementations doing validate_eof and handling the containers/headers must make assumptions about the maximum size of the container to expect and handle
  • is it MAX_INITCODE_SIZE?
  • is it 64K, same as subcontainer?
  • is it whatever can be maxed out with sections, i.e. max code sections, then max of max container sections and max data size?
  • is it some yet other value?
• for example, evmone had a subtle bug, where large top-level containers had "overflown" data_section_offset persisted in the header, because offsets were expected to not exceed 64K

Proposal

Introduce a validation rule of max top-level container size of MAX_INITCODE_SIZE 48K (or twice that constant, for practical reasons like solidity testing methods). Whenever either the bytestring being the top-level container or the declared (in the header, as discovered during header parsing) size of the top-level container exceed that, validation fails.

[chfast]

I agree.

[pdobacz]

Just got an answer from Solidity, that limiting to MAX_INITCODE_SIZE is not an issue from their POV

[pdobacz]

Opening an EIPs PR for this and #128, as well as putting adding EEST tests on my list.