[FIR IDE] Add Fir lightclasses tests and fix FindUsages tests

compiler/testData/asJava/ultraLightClasses/classModifiers.java

@@ -0,0 +1,60 @@
+public class Open /* pkg.Open*/ {
+  public  Open();//  .ctor()
+
+
+
+
+  class Private ...
+  
+    class Private2 ...
+  
+    class StaticInternal ...
+  
+  }
+
+private static final class Private /* pkg.Open.Private*/ extends pkg.Open {
+  public  Private();//  .ctor()
+
+}
+
+protected final class Private2 /* pkg.Open.Private2*/ {
+  public  Private2();//  .ctor()
+
+}
+
+public static final class StaticInternal /* pkg.Open.StaticInternal*/ {
+  public  StaticInternal();//  .ctor()
+
+}
+
+public final class OuterInternal /* pkg.OuterInternal*/ {
+  public  OuterInternal();//  .ctor()
+
+}
+
+final class TopLevelPrivate /* pkg.TopLevelPrivate*/ {
+  public  TopLevelPrivate();//  .ctor()
+
+}
+
+public abstract class Season /* pkg.Season*/ {
+  private  Season();//  .ctor()
+
+
+  class Nested ...
+  
+  }
+
+public static final class Nested /* pkg.Season.Nested*/ extends pkg.Season {
+  public  Nested();//  .ctor()
+
+}
+
+public abstract class SealedWithArgs /* pkg.SealedWithArgs*/ {
+  private final int a;
+
+  private  SealedWithArgs(int);//  .ctor(int)
+
+  public final int getA();//  getA()
+
+}