Internals: Fix remaining cppcheck errors (#6319)

Fixed the non const-related issue and added suppressions for the const
ones. With that `make cppcheck` should be clean.

src/V3Fork.cpp

@@ -548,7 +548,7 @@ class ForkVisitor final : public VNVisitor {
         return varp;
     }
 
-    AstTask* makeTask(FileLine* fl, AstNode* stmtsp, string name) {
+    AstTask* makeTask(FileLine* fl, AstNode* stmtsp, const std::string& name) {
         stmtsp = AstNode::addNext(static_cast<AstNode*>(m_capturedVarsp), stmtsp);
         AstTask* const taskp = new AstTask{fl, name, stmtsp};
         return taskp;