Effects: support cfg tests with stdlib

- Add method "doTestWithStdLib" which launches test with stdlib
- Change GenerateTests.kt to generate cfg tests with stdlib from
folders 'cfgWithStdLib' and 'cfgVariablesWithStdLib'

==========
Introduction of Effect System: 14/18

generators/src/org/jetbrains/kotlin/generators/tests/GenerateTests.kt

@@ -447,15 +447,19 @@ fun main(args: Array<String>) {
 
         testClass<AbstractControlFlowTest> {
             model("cfg")
+            model("cfgWithStdLib", testMethod = "doTestWithStdLib")
         }
 
         testClass<AbstractDataFlowTest> {
             model("cfg-variables")
+            model("cfgVariablesWithStdLib", testMethod = "doTestWithStdLib")
         }
 
         testClass<AbstractPseudoValueTest> {
             model("cfg")
+            model("cfgWithStdLib", testMethod = "doTestWithStdLib")
             model("cfg-variables")
+            model("cfgVariablesWithStdLib", testMethod = "doTestWithStdLib")
         }
 
         testClass<AbstractAnnotationParameterTest> {