@Override
	public int getInstructionLength(StartInstructionValue exp) {
		return 0;
	}
"Solves" expression of {@code inst_start}

<p>
Works like the constant solver, but takes the value of {@code inst_start}, which is given by the
assembly address.
Ghidra/Framework/SoftwareModeling/src/main/java/ghidra/app/plugin/assembler/sleigh/expr/StartInstructionValueSolver.java