Do not compute stubs when building DefaultImpls light classes

Do not build stubs when computing inner classes of a light class
This should implicitly fix a deadlock reported in KT-9907 and KT-9811

idea/idea-completion/testData/injava/InterfaceDefaultImplsNonImported.java

@@ -0,0 +1,11 @@
+public class Testing {
+    public static void test() {
+        DefaultImpl<caret>
+    }
+}
+
+// EXIST:  { lookupString: "DefaultImpls", tailText: " (defaultImpls.NonAbstractFun)" }
+// EXIST:  { lookupString: "DefaultImpls", tailText: " (defaultImpls.NonAbstractFunWithExpressionBody)" }
+// EXIST:  { lookupString: "DefaultImpls", tailText: " (defaultImpls.NonAbstractProperty)" }
+// EXIST:  { lookupString: "DefaultImpls", tailText: " (defaultImpls.NonAbstractPropertyWithBody)" }
+// ABSENT:  { lookupString: "DefaultImpls", tailText: " (defaultImpls.AllAbstract)" }

idea/idea-completion/testData/injava/mockLib/defaultImpls.kt

@@ -0,0 +1,30 @@
+package defaultImpls;
+
+interface AllAbstract {
+    val c: Int
+    fun <T> f(t: T): T
+
+    val g: Int
+
+    var g2: String
+}
+
+interface NonAbstractFun {
+    fun f() {
+
+    }
+}
+
+interface NonAbstractFunWithExpressionBody {
+    fun f() = 3
+}
+
+interface NonAbstractProperty {
+    val c: Int get() = 3
+}
+
+interface NonAbstractPropertyWithBody {
+    val c: Int get() {
+        return 3
+    }
+}