[FIR] Rename FirDeclaration.session to declarationSiteSession

compiler/tests-common/tests/org/jetbrains/kotlin/fir/AbstractFirDiagnosticTest.kt

@@ -266,7 +266,7 @@ abstract class AbstractFirDiagnosticsTest : AbstractFirBaseDiagnosticsTest() {
         val collectors = mutableMapOf<FirSession, AbstractDiagnosticCollector>()
         val result = mutableMapOf<FirFile, List<FirDiagnostic<*>>>()
         for (firFile in firFiles) {
-            val session = firFile.session
+            val session = firFile.declarationSiteSession
             val collector = collectors.computeIfAbsent(session) { createCollector(session) }
             result[firFile] = collector.collectDiagnostics(firFile).toList()
         }

compiler/tests-common/tests/org/jetbrains/kotlin/fir/FirResolveBench.kt

@@ -35,7 +35,7 @@ import kotlin.system.measureNanoTime
 
 
 fun checkFirProvidersConsistency(firFiles: List<FirFile>) {
-    for ((session, files) in firFiles.groupBy { it.session }) {
+    for ((session, files) in firFiles.groupBy { it.declarationSiteSession }) {
         val provider = session.firProvider as FirProviderImpl
         provider.ensureConsistent(files)
     }