[FIR] Resolve annotations in when expressions

compiler/testData/codegen/box/annotations/annotationOnWhen.kt

@@ -0,0 +1,16 @@
+// TARGET_BACKEND: JVM
+
+enum class SomeEnum {
+    A, B
+}
+
+@Suppress("SOMETHING")
+fun box():String {
+    val someVal = SomeEnum.A
+    @Suppress("UNNECESSARY_NOT_NULL_ASSERTION")
+    when (someVal) {
+        SomeEnum.A -> {}
+        SomeEnum.B -> {}
+    }!! // !! is used to force compile-time exhaustiveness
+    return "OK"
+}