Feature - Adds LoaderV4Instruction::Copy

[Lichtso]

Problem

A new loader-v4 instruction was added to SIMD-0167.

Summary of Changes

Adds:

• LoaderV4Instruction::Copy
• is_copy_instruction()
• copy()
• test_copy_instruction()
• process_instruction_copy()
• test_loader_instruction_copy()

[mergify]

The Firedancer team maintains a line-for-line reimplementation of the
native programs, and until native programs are moved to BPF, those
implementations must exactly match their Agave counterparts.
If this PR represents a change to a native program implementation (not
tests), please include a reviewer from the Firedancer team. And please
keep refactors to a minimum.

[mergify]

The Firedancer team maintains a line-for-line reimplementation of the
native programs, and until native programs are moved to BPF, those
implementations must exactly match their Agave counterparts.
If this PR represents a change to a native program implementation (not
tests), please include a reviewer from the Firedancer team. And please
keep refactors to a minimum.