Internals: cppcheck clean and add cppcheck_filtered

src/V3Slice.cpp

@@ -417,6 +417,7 @@ class SliceVisitor : public AstNVisitor {
 		    AstNode* lhsp = new AstArraySel(nodep->fileline(),
 						    nodep->lhsp()->cloneTree(false),
 						    index++);
+		    // cppcheck-suppress nullPointer
 		    newp = newp->addNext(nodep->cloneType(lhsp, subp->unlinkFrBack()));
 		}
 		//if (debug()>=9) newp->dumpTreeAndNext(cout, "-InitArrayOut: ");