Investigate runtime change to stop invoking the loader to then invoke the BPF program

[buffalojoec]

Currently, loader programs serve two sets of instructions: account management and invoking BPF programs.

The account management instruction set can be split out and migrated to a BPF program, but that leaves the invocation of BPF programs. However, this can maybe be absorbed into the runtime.

Builtin programs use an "empty" rBPF VM to invoke their builtin functions, however this use of the VM may not be necessary. The primary purpose of the VM here was to enforce a standard interface, but if we can enforce the interface without the actual VM, then we don't need to invoke, for example, BPFLoader v3 when we wish to invoke a BPF program.

BPF programs would just be invoked directly by the runtime without first going through the mocked-up VM.

For more context, see the following:

• Owner checks during invoke setup (invoke context).
• Invocation of the owner program (BPF Loader in case of on-chain programs) using "empty" VM.
• BPF Loader program processor, where it determines which instruction set to process.
• Invocation of the BPF program with another (real) VM.