public boolean isBranch() {
		return index == -1;
	}
Check if the p-code program has executed a branch

<p>
Branches can be internal, i.e., within the current program, or external, i.e., to another
machine instructions. This refers strictly to the latter.

@see #isFallThrough()
@see #isFinished()
@return true if the program completed with an external branch
Ghidra/Framework/Emulation/src/main/java/ghidra/pcode/exec/PcodeFrame.java