[Test] Save IR bytecode dumps from BytecodeListingHandler to .ir.txt file instead of _ir.txt

This is needed to keep consistency with other dumps and to allow
  test helper plugin to recognize those dumps

plugins/allopen/testData/bytecodeListing/anonymousObject.ir.txt

@@ -0,0 +1,36 @@
+@java.lang.annotation.Retention(value=RUNTIME)
+@kotlin.Metadata
+public annotation class AllOpen {
+    // source: 'anonymousObject.kt'
+}
+
+@kotlin.Metadata
+public final class Test$a$1 {
+    // source: 'anonymousObject.kt'
+    enclosing method Test.<init>()V
+    inner (anonymous) class Test$a$1
+    method <init>(): void
+    public method run(): void
+}
+
+@kotlin.Metadata
+public final class Test$b$1 {
+    // source: 'anonymousObject.kt'
+    enclosing method Test.b()V
+    inner (anonymous) class Test$b$1
+    method <init>(): void
+    public method run(): void
+}
+
+@AllOpen
+@kotlin.Metadata
+public class Test {
+    // source: 'anonymousObject.kt'
+    private final @org.jetbrains.annotations.NotNull field a: java.lang.Runnable
+    inner (anonymous) class Test$a$1
+    inner (anonymous) class Test$b$1
+    public method <init>(): void
+    private final static method b$lambda$0(): void
+    public method b(): void
+    public @org.jetbrains.annotations.NotNull method getA(): java.lang.Runnable
+}