Minor, fix kapt test data on comments

ClassFileToSourceStubConverter relies on JvmDeclarationOrigin which is
used in the codegen, and that origin has slightly changed for the
synthetic '$annotations' method (see
`MemberCodegen.generateSyntheticAnnotationsMethod`) in e9b50157

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

@@ -83,6 +83,9 @@ public final class Test {
     java.lang.String a) {
     }
 
+    /**
+     * prop2.
+     */
     @Anno()
     public static void prop2$annotations() {
     }