Remove `runCode` API from codebase

[acolytec3]

In evm there are currently two separate ways to execute bytecode. runCall and runCode. runCode is a legacy of past days when the vm package was more tightly bound to evm. This code is obsolete and unused other than in examples and tests. We should remove it entirely from the code base.

The right solution would do the following:

• Remove the code itself and the associated types from evm
• Remove any examples that reference runCode
• Remove any tests that only test runCode functionality
• Revise other tests like here that use runCode to instead use runCall. Likely the only difference will be ensuring the returned value from runCall accesses the result.execResult instead of just result.

[holgerd77]

This is part of the public API and therefore breaking change which we cannot tackle anytime soon.

Have re-labelled accordingly, also removed the "help wanted" and first-issue labels, so that people do not start on it.