Fix #13711 fuzzing crash (null-pointer-use) in Tokenizer::simplifyCompoundStatements() (#8099)

Author: chrchr-github

lib/tokenize.cpp

@@ -5707,6 +5707,8 @@ bool Tokenizer::simplifyTokenList1(const char FileName[])
     if (isCPP())
         simplifyExternC();
 
+    validate();
+
     // simplify compound statements: "[;{}] ( { code; } ) ;"->"[;{}] code;"
     simplifyCompoundStatements();
 

test/cli/fuzz-crash/crash-be54fe1da04e7a624214b58f3b572b87082a2e93

@@ -0,0 +1 @@
+(({}namespace d=n));