Java: don't consider constructors used when the class is used externally (IDEA-206602)

for global "Unused declaration" inspection

GitOrigin-RevId: e671cef5b81a2e148ec747e91e876959c0481d8d

java/java-tests/testData/inspection/deadCode/SCR9690/ext_src/B.java

@@ -1,3 +1,7 @@
 class B extends A {
+
+  public static void main(String[] args) {
+    new B();
+  }
 }
 

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

@@ -0,0 +1,9 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<problems>
+  <problem>
+    <file>UsefulClass.java</file>
+    <line>4</line>
+    <entry_point TYPE="method" FQNAME="a.UsefulClass UsefulClass()" />
+    <description>Constructor is never used.</description>
+  </problem>
+</problems>

java/java-tests/testData/inspection/deadCode/externallyUsedClass/src/a/UsefulClass.java

@@ -0,0 +1,6 @@
+package a;
+
+public class UsefulClass {
+    public UsefulClass() {
+    }
+}

java/java-tests/testData/inspection/deadCode/externallyUsedClass/test_src/b/Another.java

@@ -0,0 +1,6 @@
+package b;
+
+import a.UsefulClass;
+
+public class Another {
+}