fix #13881: Stack overflow in findTokensSkipDeadCodeImpl() (danmar#7545)

This
```
using A::a;
int x = B<T>::a;
```
would previously be simplified to
```
int x = B<T>A::a;
```
in `simplifyUsing`.

Author: ludviggunne

lib/tokenize.cpp

@@ -2650,6 +2650,10 @@ namespace {
             return false;
         }
 
+        if (Token::simpleMatch(tok1->tokAt(-2), "> ::")) {
+            return false;
+        }
+
         if (Token::Match(tok1, "%name% (") && TokenList::isFunctionHead(tok1->next(), "{;:")) {
             if (Token::Match(tok1->previous(), "%name%") && !tok1->previous()->isControlFlowKeyword())
                 return false;

test/testnullpointer.cpp

@@ -140,6 +140,7 @@ class TestNullPointer : public TestFixture {
         TEST_CASE(nullpointer101);        // #11382
         TEST_CASE(nullpointer102);
         TEST_CASE(nullpointer103);
+        TEST_CASE(nullpointer104); // #13881
         TEST_CASE(nullpointer_addressOf); // address of
         TEST_CASE(nullpointerSwitch); // #2626
         TEST_CASE(nullpointer_cast); // #4692
@@ -2919,6 +2920,15 @@ class TestNullPointer : public TestFixture {
         TODO_ASSERT_EQUALS("", "[test.cpp:3:10]: (warning) Possible null pointer dereference: p [nullPointer]\n", errout_str());
     }
 
+    void nullpointer104() // #13881
+    {
+        check("using std::max;\n"
+              "void f(int i) {\n"
+              "    const size_t maxlen = i == 1 ? 8 : (std::numeric_limits<std::size_t>::max());\n"
+              "}\n");
+        ASSERT_EQUALS("", errout_str());
+    }
+
     void nullpointer_addressOf() { // address of
         check("void f() {\n"
               "  struct X *x = 0;\n"

test/testsimplifyusing.cpp

@@ -71,6 +71,7 @@ class TestSimplifyUsing : public TestFixture {
         TEST_CASE(simplifyUsing33);
         TEST_CASE(simplifyUsing34);
         TEST_CASE(simplifyUsing35);
+        TEST_CASE(simplifyUsing36);
 
         TEST_CASE(simplifyUsing8970);
         TEST_CASE(simplifyUsing8971);
@@ -873,6 +874,14 @@ class TestSimplifyUsing : public TestFixture {
         ASSERT_EQUALS("", errout_str());
     }
 
+    void simplifyUsing36() {
+        const char code[] = "using A::a;\n"
+                            "int c = B<int>::a;\n";
+        const char expected[] = "int c ; c = B < int > :: a ;";
+        ASSERT_EQUALS(expected, tok(code));
+        ASSERT_EQUALS("", errout_str());
+    }
+
     void simplifyUsing8970() {
         const char code[] = "using V = std::vector<int>;\n"
                             "struct A {\n"