[FIR] Add separate local scope for init blocks

compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/transformers/body/resolve/FirDeclarationsResolveTransformer.kt

@@ -451,6 +451,7 @@ class FirDeclarationsResolveTransformer(transformer: FirBodyResolveTransformer)
         return withLocalScopeCleanup {
             dataFlowAnalyzer.enterInitBlock(anonymousInitializer)
             addLocalScope(primaryConstructorParametersScope)
+            addLocalScope(FirLocalScope())
             transformDeclaration(anonymousInitializer, ResolutionMode.ContextIndependent).also {
                 dataFlowAnalyzer.exitInitBlock(it.single as FirAnonymousInitializer)
             }

compiler/testData/diagnostics/tests/AnonymousInitializers.fir.kt

@@ -20,7 +20,7 @@ class WithC() {
   val a : Int get() = 1
 
   init {
-    val z = b
+    val z = <!UNRESOLVED_REFERENCE!>b<!>
     val zz = x
   }
 }

compiler/testData/diagnostics/tests/controlFlowAnalysis/assignmentInLocalsInConstructor.fir.kt

@@ -57,8 +57,8 @@ class Test5 {
 
     init {
         val x: String
-        <!UNRESOLVED_REFERENCE!>x<!> = ""
-        z = <!UNRESOLVED_REFERENCE!>x<!>
+        x = ""
+        z = x
     }
 
     constructor(y: Int) {

compiler/testData/diagnostics/tests/smartCasts/varInInitNoPrimary.fir.kt

@@ -1,11 +1,11 @@
 class Your {
     init {
         var y: String? = "xyz"
-        if (<!UNRESOLVED_REFERENCE!>y<!> != null) {
+        if (y != null) {
             // Bug that should be fixed
             // Problem: descriptorToDeclaration cannot get here init block by its descriptor
             // See PreliminaryDeclarationVisitor.getVisitorByVariable
-            <!UNRESOLVED_REFERENCE!>y<!>.<!UNRESOLVED_REFERENCE!>hashCode<!>()
+            y.hashCode()
         }
     }