[FIR] Fix tests data for diagnostic tests

For tests failed after light tree changes

compiler/testData/diagnostics/tests/incompleteCode/diagnosticWithSyntaxError/checkBackingFieldException.fir.kt

@@ -0,0 +1,18 @@
+package h
+
+class Square() {
+  var size : Double =
+  <!UNRESOLVED_REFERENCE!>set<!>(<!UNRESOLVED_REFERENCE!>value<!>) {
+    //in LT this LAMBDA_EXPRESSION get parsed lazyly, but doesn't got anywhere in FIR tree (as property doesn't have place for it)
+    <!SYNTAX{PSI}!>$area<!> <!SYNTAX{PSI}!>= size * size<!>
+  }
+
+  <!MUST_BE_INITIALIZED_OR_BE_ABSTRACT!>var area : Double<!>
+  private set
+}
+
+fun main() {
+  val s = Square()
+
+  s.size = 2.0
+}

compiler/testData/diagnostics/tests/incompleteCode/diagnosticWithSyntaxError/checkBackingFieldException.kt

@@ -1,11 +1,10 @@
-// FIR_IDENTICAL
 package h
 
 class Square() {
   var size : Double =
   <!UNRESOLVED_REFERENCE!>set<!>(<!UNRESOLVED_REFERENCE!>value<!>) {
     //in LT this LAMBDA_EXPRESSION get parsed lazyly, but doesn't got anywhere in FIR tree (as property doesn't have place for it)
-    <!SYNTAX{PSI}!>$area<!> <!SYNTAX{PSI}!>= size * size<!>
+    <!SYNTAX!>$area<!> <!SYNTAX!>= size * size<!>
   }
 
   <!MUST_BE_INITIALIZED_OR_BE_ABSTRACT!>var area : Double<!>