unused declaration: add test for static import (IDEA-143882)

java/java-tests/testData/inspection/deadCode/staticImport/expected.xml

@@ -0,0 +1,10 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<problems>
+  <problem>
+    <file>Holder.java</file>
+    <line>4</line>
+    <problem_class severity="WARNING" attribute_key="NOT_USED_ELEMENT_ATTRIBUTES">unused declaration</problem_class>
+    <description>Method is never used.</description>
+  </problem>
+</problems>
+

java/java-tests/testData/inspection/deadCode/staticImport/src/Usage.java

@@ -0,0 +1,7 @@
+import static holder.Holder.*;
+
+public class Usage {
+   public static void main(String[] args) {
+      System.out.println(CONST);
+   }
+}

java/java-tests/testData/inspection/deadCode/staticImport/src/holder/Holder.java

@@ -0,0 +1,5 @@
+package holder;
+public class Holder {
+   public static final String CONST = "JB";
+   public String method() { return "JB"; }
+}

java/java-tests/testSrc/com/intellij/java/codeInspection/UnusedDeclarationTest.java

@@ -206,4 +206,8 @@ public class UnusedDeclarationTest extends AbstractUnusedDeclarationTest {
   public void testReferenceFromGroovy() {
     doTest();
   }
+
+  public void testStaticImport() {
+    doTest();
+  }
 }