"Find Usages": add tests for Kotlin usages of Java declarations

idea/testData/findUsages/java/findJavaFieldUsages/JKFieldUsages.0.java

@@ -0,0 +1,5 @@
+// PSI_ELEMENT: com.intellij.psi.PsiField
+// OPTIONS: readAccess
+public class A {
+    public String <caret>foo = "foo";
+}