FIR: copy builder inference session when creating snapshot for locals

This commit fixes one builder inference case from KT-49925

compiler/testData/codegen/box/inference/builderInference/builderCallAsReturnTypeInLocalClass.kt

@@ -1,6 +1,4 @@
 // WITH_STDLIB
-// IGNORE_BACKEND_FIR: JVM_IR
-// FIR status: NEW_INFERENCE_NO_INFORMATION_FOR_PARAMETER on buildList calls (E)
 @OptIn(ExperimentalStdlibApi::class)
 fun foo1() {
     buildList {

compiler/testData/codegen/box/inference/builderInference/kt48633.kt

@@ -1,6 +1,4 @@
 // DONT_TARGET_EXACT_BACKEND: WASM
-// IGNORE_BACKEND_FIR: JVM_IR
-// FIR status: NEW_INFERENCE_NO_INFORMATION_FOR_PARAMETER on buildList call (E)
 // WITH_STDLIB
 
 class TowerDataElementsForName() {