private AddressSetView checkExecBlocks(Program program, AddressSetView set) {
		// check if there is a block marked unexec

		AddressSet execSet = new AddressSet();
		MemoryBlock blocks[] = program.getMemory().getBlocks();
		for (MemoryBlock block : blocks) {
			if (block.isExecute()) {
				execSet.addRange(block.getStart(), block.getEnd());
			}
		}

		if (execSet.isEmpty()) {
			return set;
		}
		return set.intersect(execSet);
	}
Check if there are blocks marked executable.
  If there are exec blocks, remove all un-exec blocks from the set.
@param program
@param set
Ghidra/Features/Base/src/main/java/ghidra/app/plugin/prototype/analysis/AggressiveInstructionFinderAnalyzer.java