Kapt: remove old JVM backend test data (2/2)

In this commit, .ir.txt expectation test data files for the JVM IR
backend are renamed to .txt. This is done as two separate commits so
that Git would recognize that these files were logically moved, not that
the contents of the original .txt files were changed.

 #KT-64680

plugins/kapt3/kapt3-compiler/testData/converter/errorSuperclass.txt

@@ -0,0 +1,54 @@
+package test;
+
+@java.lang.annotation.Retention(value = java.lang.annotation.RetentionPolicy.RUNTIME)
+/**
+ * internal final annotation class test/Anno : kotlin/Annotation {
+ *
+ *   // signature: <init>()V
+ *   public constructor()
+ *
+ *   // module name: main
+ * }
+ */
+@kotlin.Metadata()
+public abstract @interface Anno {
+}
+
+////////////////////
+
+package test;
+
+@Anno()
+/**
+ * internal final class test/ClassWithParent : kotlin/CharSequence {
+ *
+ *   // signature: <init>()V
+ *   public constructor()
+ *
+ *   // module name: main
+ * }
+ */
+@kotlin.Metadata()
+@kotlin.Suppress(names = {"UNRESOLVED_REFERENCE"})
+public final class ClassWithParent implements java.lang.CharSequence {
+
+    public ClassWithParent() {
+        super();
+    }
+
+    @java.lang.Override()
+    public abstract char get(int index);
+
+    @java.lang.Override()
+    public abstract int getLength();
+
+    @java.lang.Override()
+    public final char charAt(int index) {
+        return '\u0000';
+    }
+
+    @java.lang.Override()
+    public final int length() {
+        return 0;
+    }
+}