[LL API] Fix smart-cast collection for special 'FirElement's

'DFANode' is not created for certain elements, such as types or
references. Before the change, only the target element itself was
queried for DFA, making the 'ContextCollector' return an empty map of
smart casts.

^KTIJ-26973 Fixed

analysis/low-level-api-fir/testData/contextCollector/smartCasts/onLabel.txt

@@ -0,0 +1,52 @@
+Tower Data Context:
+    Element 0
+        Scope: FirDefaultStarImportingScope
+    Element 1
+        Scope: FirDefaultSimpleImportingScope
+    Element 2
+        Scope: FirExplicitStarImportingScope
+    Element 3
+        Scope: FirDefaultSimpleImportingScope
+    Element 4
+        Scope: FirDefaultSimpleImportingScope
+    Element 5
+        Scope: FirPackageMemberScope
+    Element 6
+        Scope: FirExplicitSimpleImportingScope
+    Element 7
+        Scope: FirLocalScope
+            Properties:
+                FirValueParameterSymbol a: R|kotlin/Any|
+    Element 8
+        Scope: FirLocalScope
+            Properties:
+                FirPropertySymbol lvar result: R|kotlin/Int|
+Smart Casts:
+    FirValueParameterSymbol a: R|kotlin/Any|
+    Types:
+        Foo
+        kotlin/Any
+
+FILE: [ResolvedTo(IMPORTS)] onLabel.kt
+    public final [ResolvedTo(BODY_RESOLVE)] fun test([ResolvedTo(BODY_RESOLVE)] a: R|kotlin/Any|): R|kotlin/Unit| {
+        when () {
+            (R|<local>/a| !is R|Foo|) ->  {
+                ^test Unit
+            }
+        }
+
+        [ResolvedTo(BODY_RESOLVE)] lvar result: R|kotlin/Int| = Int(0)
+        loop@while(Boolean(true)) {
+            when () {
+                R|<local>/a|.R|/Foo.process|().R|kotlin/Boolean.not|() ->  {
+                    break@@@[Boolean(true)]
+                }
+            }
+
+        }
+
+    }
+    public abstract [ResolvedTo(STATUS)] interface Foo : R|kotlin/Any| {
+        public abstract [ResolvedTo(CONTRACTS)] fun process(): R|kotlin/Boolean|
+
+    }