Do not wrap built-in function in JetLightClass (EA-38770)

Built-in top-level functions are located in jet.namespace class.
JetStandardClasses.isStandardClass() now checks that a given fqName starts with
"jet.", instead of searching it in the standard scope, to prevent this kind of
errors in the future

compiler/frontend/src/org/jetbrains/jet/lang/types/lang/JetStandardClasses.java

@@ -613,11 +613,6 @@ public class JetStandardClasses {
     }
 
     public static boolean isStandardClass(@NotNull FqName fqName) {
-        for (DeclarationDescriptor descriptor : getAllStandardClasses()) {
+        return JetStandardClasses.STANDARD_CLASSES_FQNAME.equals(fqName.parent());
-            if (DescriptorUtils.getFQName(descriptor).equals(fqName.toUnsafe())) {
-                return true;
-            }
-        }
-        return false;
     }
 }

idea/testData/javaFacade/ea38770.kt

@@ -0,0 +1,3 @@
+fun <T> foo() {
+    T.<caret>toString()
+}

idea/tests/org/jetbrains/jet/plugin/javaFacade/JetJavaFacadeTest.java

@@ -87,6 +87,19 @@ public class JetJavaFacadeTest extends LightCodeInsightFixtureTestCase {
         doTestWrapClass();
     }
 
+    public void testEa38770() {
+        myFixture.configureByFile(getTestName(true) + ".kt");
+
+        PsiReference reference = myFixture.getFile().findReferenceAt(myFixture.getCaretOffset());
+        assertNotNull(reference);
+        PsiElement element = reference.resolve();
+        assertNotNull(element);
+        assertInstanceOf(element, JetNamedFunction.class);
+        JetNamedFunction toString = (JetNamedFunction) element;
+
+        assertNull("There should be no wrapper for built-in function", JetLightClass.wrapMethod(toString));
+    }
+
     public void testInnerClass() throws Exception {
         myFixture.configureByFile(getTestName(true) + ".kt");