Runtime sha256 should work for arbitrary strings even with length >= 128

[anton-trunov]

sha256 at run-time uses the SHA256U TVM instruction, which only works with data with up to 1023 bits, so strings of length 128 bytes basically get truncated. This is confusing for smart-contract authors because it breaks the abstraction of the String type. Since we allow strings with more than 127 characters, those sha256 should work on those.

See also, #1085

[novusnota]

The statically known strings is one story, where we can accurately compute their hashes with sha256_sync() no matter their length. And FunC can do the same with their "..."H string. But the run-time strings is a different case.

Do you mean to check the length of the string at runtime somehow?

[anton-trunov]

Do you mean to check the length of the string at runtime somehow?

the implementation should traverse all the chunks of the string

[anton-trunov]

related issue: #1085