Fix #13702, #13713 fuzzing crashes (danmar#8071)

Co-authored-by: chrchr-github <noreply@github.com>

Author: chrchr-github

lib/symboldatabase.cpp

@@ -1508,7 +1508,10 @@ void SymbolDatabase::createSymbolDatabaseIncompleteVars()
                 continue;
             }
             if (tok->str() == "using") {
-                tok = Token::findsimplematch(tok, ";");
+                Token* usingEnd = Token::findsimplematch(tok, ";");
+                if (!usingEnd)
+                    mTokenizer.syntaxError(tok);
+                tok = usingEnd;
                 continue;
             }
         }

lib/tokenize.cpp

@@ -8940,6 +8940,8 @@ void Tokenizer::findGarbageCode() const
             syntaxError(tok);
         if (Token::Match(tok, ": [)]=]"))
             syntaxError(tok);
+        if (Token::simpleMatch(tok, ", :"))
+            syntaxError(tok);
         if (Token::Match(tok, "typedef [,;:]"))
             syntaxError(tok);
         if (Token::Match(tok, "!|~ %comp%") &&

test/cli/fuzz-crash/crash-04f8bc02d0683e12579485090f4a2cbc55d3c955

@@ -0,0 +1 @@
+b f(){using e}

test/cli/fuzz-crash/crash-3de394576af6f9f7ca95bdd282075d06f980252f

@@ -0,0 +1 @@
+t o(){for(u*e,:c)t c=e;}