EIP-4844 Spec Change: Update z + y Precompile vectors to big endian.

[spencer-tb]

Functional change in accordance with the future spec update, to modify the z + y precompile vectors such that they are big endian: ethereum/EIPs#7020

Following a discussion ACD on may 11, it was decided to specify z and y in pre-compile input to be big endian so that there is minimal confusion on EL which primarily encodes bytes as big endian.

The PR adds a python file (for now) which toggles the endianess of the z + y vectors in

fillers/eips/eip4844/point_evaluation_vectors/go_kzg_4844_verify_kzg_proof.json

It can be run simply with:

python toggle_precompile_endianess.py

The first commit in this PR changes these values to big endian. If the python script is run again it will toggle it back to little endian, and so on.

[spencer-tb]

Tagging the following task: #130

Specify precompile input's z and y to be encoded as big endian.

This PR will not be merged until both the spec change ethereum/EIPs#7020, geth is updated to match the new spec.

[spencer-tb]

The following error is received when filling the precompile tests with the update values:

>> raise Storage.KeyValueMismatch(
ethereum_test_tools.common.types.Storage.KeyValueMismatch:
incorrect value for key
0x0000000000000000000000000000000000000000000000000000000000000001: want
0x0000000000000000000000000000000000000000000000000000000000001000, 
got 
0x01190503c43205b479ab7b9724143c39ec4a58a56457777d65a6eb4dd70285b9 

This error will hopefully be resolved after updating geth t8n-tool.

[spencer-tb]

This change only affect the following test subset:
point_evaluation_precompile_external_vectors.json

[spencer-tb]

Closing this as the changes have been added to the pytest merge ae5df2f.