IDEA-133946 Don't highlight private constructor as unused if it is called by dependency injection engine

java/java-tests/testData/codeInsight/daemonCodeAnalyzer/advHighlighting/Unused.java

@@ -2,6 +2,13 @@ class a extends Exception {
   private <warning descr="Private constructor 'a(java.lang.String)' is never used">a</warning>(String s) {
     super(s);
   }
+  private <warning descr="Private constructor 'a()' is never used">a</warning>(){}
+}
+
+class TheOnlyCtr extends Exception {
+  private TheOnlyCtr(String s) {
+    super(s);
+  }
 }
 
 class s extends Exception {

java/java-tests/testData/codeInsight/daemonCodeAnalyzer/unusedDecls/PrivateConstructor.java

@@ -0,0 +1,14 @@
+import java.lang.Override;
+
+class PrivateConstructor {
+  private final int myA;
+
+  private PrivateConstructor(int a) {
+    myA = a;
+  }
+
+  @Override
+  public int hashCode() {
+    return myA;
+  }
+}