Remove Android api diagnostic error on Kotlin interface default methods

They don't require java 8 or any other special support to work on Android

#KT-18059 Fixed

Author: 4u7

idea/testData/android/lint/apiCheck.kt

@@ -476,4 +476,11 @@ fun testJava8() {
 
     // Ok, Kotlin
     mapOf(1 to 2).forEach { (key, value) -> key + value }
+}
+
+interface WithDefault {
+    // Should be ok
+    fun methodWithBody() {
+        return
+    }
 }

plugins/lint/lint-checks/src/com/android/tools/klint/checks/ApiDetector.java

@@ -982,24 +982,6 @@ private void checkCast(@NonNull UElement node, @NonNull PsiClassType classType,
             mContext.report(UNSUPPORTED, location, message);
         }
 
-        @Override
-        public boolean visitMethod(@NotNull UMethod method) {
-            // API check for default methods
-            if (method.getModifierList().hasExplicitModifier(PsiModifier.DEFAULT)) {
-                int api = 24; // minSdk for default methods
-                int minSdk = getMinSdk(mContext);
-
-                if (!isSuppressed(api, method, minSdk, mContext, UNSUPPORTED)) {
-                    Location location = mContext.getLocation(method);
-                    String message = String.format("Default method requires API level %1$d "
-                                                   + "(current min is %2$d)", api, minSdk);
-                    mContext.reportUast(UNSUPPORTED, method, location, message);
-                }
-            }
-
-            return super.visitMethod(method);
-        }
-
         @Override
         public boolean visitClass(@NotNull UClass aClass) {
             // Check for repeatable annotations