search for Kotlin convention usages of Java methods

#KT-5960 Fixed

idea/testData/findUsages/java/findJavaMethodUsages/ConventionUsages.0.java

@@ -0,0 +1,7 @@
+// PSI_ELEMENT: com.intellij.psi.PsiMethod
+// OPTIONS: usages
+public class Small {
+    public boolean c<caret>ontains(String str) { // Call "Find usages" for this method
+        return true;
+    }
+}