KT-62675 [AA] Handle labeled this expressions in reference shortener

At the moment, there is no good way to meaningfully filter `this`
expressions. The filters for the reference shortener can work only with
symbols, and it does not make a lot of sense to check any particular
symbol when deciding whether to shorten a labeled `this` expression.

We would probably need a better API for the shortener to be able
to filter more precisely (see KT-63555)

^KT-62675 Fixed

analysis/analysis-api-impl-base/tests/org/jetbrains/kotlin/analysis/api/impl/base/test/cases/references/ShorteningResultsRenderer.kt

@@ -24,6 +24,11 @@ internal object ShorteningResultsRenderer {
                 appendLine("[qualifier] $it${shortenedRef?.let { ref -> " -> $ref" } ?: ""}")
             }
         }
+        shortening.thisLabelsToShorten.forEach { thisLabel ->
+            thisLabel.labelToShorten.element?.text?.let {
+                appendLine("[thisLabel] $it")
+            }
+        }
         shortening.kDocQualifiersToShorten.forEach { kdoc ->
             kdoc.element?.text?.let {
                 appendLine("[kdoc] $it")