Always consider container's experimentality in ExperimentalUsageChecker

This results in more diagnostics usually, but allows library authors to
avoid annotating everything in each experimental class with the marker
(only the class needs to be annotated now)

 #KT-22759

compiler/testData/diagnostics/testsWithStdLib/experimental/deeplyNestedClass.kt

@@ -0,0 +1,61 @@
+// !API_VERSION: 1.3
+// MODULE: api
+// FILE: api.kt
+
+package api
+
+@Experimental(Experimental.Level.WARNING, [Experimental.Impact.COMPILATION])
+@Target(AnnotationTarget.CLASS, AnnotationTarget.FUNCTION)
+annotation class ExperimentalAPI
+
+@ExperimentalAPI
+class C {
+    class D {
+        class E {
+            class F
+        }
+    }
+}
+
+// MODULE: usage1(api)
+// FILE: usage-propagate.kt
+
+package usage1
+
+import api.*
+
+@ExperimentalAPI
+fun use1() {
+    C.D.E.F()
+}
+
+@ExperimentalAPI
+fun use2(f: C.D.E.F) = f.hashCode()
+
+// MODULE: usage2(api)
+// FILE: usage-use.kt
+
+package usage2
+
+import api.*
+
+@UseExperimental(ExperimentalAPI::class)
+fun use1() {
+    C.D.E.F()
+}
+
+@UseExperimental(ExperimentalAPI::class)
+fun use2(f: <!EXPERIMENTAL_API_USAGE!>C<!>.<!EXPERIMENTAL_API_USAGE!>D<!>.<!EXPERIMENTAL_API_USAGE!>E<!>.<!EXPERIMENTAL_API_USAGE!>F<!>) = f.hashCode()
+
+// MODULE: usage3(api)
+// FILE: usage-none.kt
+
+package usage3
+
+import api.*
+
+fun use1() {
+    <!EXPERIMENTAL_API_USAGE!>C<!>.<!EXPERIMENTAL_API_USAGE!>D<!>.<!EXPERIMENTAL_API_USAGE!>E<!>.<!EXPERIMENTAL_API_USAGE!>F<!>()
+}
+
+fun use2(f: <!EXPERIMENTAL_API_USAGE!>C<!>.<!EXPERIMENTAL_API_USAGE!>D<!>.<!EXPERIMENTAL_API_USAGE!>E<!>.<!EXPERIMENTAL_API_USAGE!>F<!>) = f.<!EXPERIMENTAL_API_USAGE!>hashCode<!>()