fix: prevent NPE while processing try/catch regions (#673)

jadx-core/src/main/java/jadx/core/dex/visitors/regions/RegionMaker.java

@@ -954,6 +954,9 @@ public class RegionMaker {
 			Set<BlockNode> exits = new HashSet<>();
 			for (BlockNode splitter : splitters) {
 				for (BlockNode handler : blocks) {
+					if (handler.contains(AFlag.REMOVE)) {
+						continue;
+					}
 					List<BlockNode> s = splitter.getSuccessors();
 					if (s.isEmpty()) {
 						LOG.debug(ErrorsCounter.formatMsg(mth, "No successors for splitter: " + splitter));

jadx-core/src/main/java/jadx/core/utils/BlockUtils.java

@@ -432,6 +432,9 @@ public class BlockUtils {
 		if (b1 == null || b2 == null) {
 			return null;
 		}
+		if (b1.getDomFrontier() == null || b2.getDomFrontier() == null) {
+			return null;
+		}
 		BitSet b = new BitSet();
 		b.or(b1.getDomFrontier());
 		b.and(b2.getDomFrontier());