JVM IR: Mark annotation implementation classes as anonymous

And add tests to ensure that annotation implementation classes are
handled correctly in jvm-abi-gen.

plugins/jvm-abi-gen/testData/content/annotationInstantiation/directives.txt

@@ -0,0 +1,3 @@
+// LANGUAGE_VERSION: 1.6
+// IGNORE_BACKEND_LEGACY: JVM
+// IGNORE_BACKEND: JVM

plugins/jvm-abi-gen/testData/content/annotationInstantiation/signatures.txt

@@ -0,0 +1,23 @@
+@java.lang.annotation.Retention(value=RUNTIME)
+@kotlin.Metadata
+public annotation class test/A {
+    // source: 'test.kt'
+}
+@kotlin.Metadata
+public synthetic final class test/Test$annotationImpl$test_A$0 {
+    // source: 'test.kt'
+    enclosing class test/Test
+    inner (anonymous) class test/Test$annotationImpl$test_A$0
+    public method <init>(): void
+    public synthetic final method annotationType(): java.lang.Class
+    public final method equals(@org.jetbrains.annotations.Nullable p0: java.lang.Object): boolean
+    public final method hashCode(): int
+    public final @org.jetbrains.annotations.NotNull method toString(): java.lang.String
+}
+@kotlin.Metadata
+public final class test/Test {
+    // source: 'test.kt'
+    inner (anonymous) class test/Test$annotationImpl$test_A$0
+    public method <init>(): void
+    public final @org.jetbrains.annotations.NotNull method annotationInstantiation(): test.A
+}

plugins/jvm-abi-gen/testData/content/annotationInstantiation/test.kt

@@ -0,0 +1,7 @@
+package test
+
+annotation class A
+
+class Test {
+    inline fun annotationInstantiation() = A()
+}