Set correct IR origins for inc/dec operations

NB: in order to produce correct IR origins, the source element kinds for
some FIR elements has been changed. As a side effect, mapping PSI to FIR
slightly changed: namely, for `a[b]++`, `a[b]` used to be mapped on
`set` call or callable reference, but now it is mapped on `get` call.

^KT-61891: Fixed
^KT-64387: Fixed

compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/collectors/components/ErrorNodeDiagnosticCollectorComponent.kt

@@ -162,7 +162,7 @@ class ErrorNodeDiagnosticCollectorComponent(
         }
 
         // Prefix inc/dec on array access will have two calls to .get(...), don't report for the second one.
-        if (source?.kind == KtFakeSourceElementKind.DesugaredPrefixSecondGetReference) {
+        if (source?.kind is KtFakeSourceElementKind.DesugaredPrefixSecondGetReference) {
             return
         }