FIR: Minor. Drop unused getWholeQualifierSourceIfPossible

compiler/fir/tree/src/org/jetbrains/kotlin/fir/Utils.kt

@@ -58,37 +58,5 @@ fun <R : FirTypeRef> R.copyWithNewSourceKind(newKind: FirFakeSourceElementKind):
     } as R
 }
 
-/**
- * Let's take `a.b.c.call()` expression as an example.
- *
- * This function allows to transform `SourceElement(psi = 'a')` to `SourceElement(psi = 'a.b.c')`
- * ([stepsToWholeQualifier] should be = 2 for that).
- *
- * @receiver original source element
- * @param stepsToWholeQualifier distance between the original psi and the whole qualifier psi
- */
-fun FirSourceElement.getWholeQualifierSourceIfPossible(stepsToWholeQualifier: Int): FirSourceElement {
-    if (stepsToWholeQualifier == 0) return this
-    return when (this) {
-        is FirRealPsiSourceElement -> {
-            val qualifiersChain = generateSequence(psi) { it.parent }
-            val wholeQualifier = qualifiersChain.elementAt(stepsToWholeQualifier)
-            wholeQualifier.toFirPsiSourceElement() as FirRealPsiSourceElement
-        }
-        is FirLightSourceElement -> {
-            val qualifiersChain = generateSequence(lighterASTNode) { treeStructure.getParent(it) }
-            val wholeQualifier = qualifiersChain.elementAt(stepsToWholeQualifier)
-            wholeQualifier.toFirLightSourceElement(
-                treeStructure,
-                startOffset = this.startOffset,
-                endOffset = wholeQualifier.endOffset + (this.endOffset - this.lighterASTNode.endOffset)
-            )
-        }
-        is FirFakeSourceElement -> {
-            this
-        }
-    }
-}
-
 val FirFile.packageFqName: FqName
     get() = packageDirective.packageFqName