do not generate models for toString

Author: owen-mc

java/ql/lib/semmle/code/java/dataflow/internal/ModelExclusions.qll

@@ -64,6 +64,7 @@ predicate isUninterestingForModels(Callable c) {
   isInTestFile(c.getCompilationUnit().getFile()) or
   isInternal(c.getCompilationUnit()) or
   c instanceof MainMethod or
+  c instanceof ToStringMethod or
   c instanceof StaticInitializer or
   exists(FunctionalExpr funcExpr | c = funcExpr.asMethod()) or
   c.getDeclaringType() instanceof TestLibrary or