[FIR] Add FINAL_UPPER_BOUND checker

compiler/tests-spec/testData/diagnostics/notLinked/contracts/declarations/contractBuilder/effects/returns/neg/5.fir.kt

@@ -3,7 +3,7 @@
 import kotlin.contracts.*
 
 // TESTCASE NUMBER: 1
-fun <T : Boolean>T.case_1(): Boolean? {
+fun <T : <!FINAL_UPPER_BOUND!>Boolean<!>>T.case_1(): Boolean? {
     contract { <!ERROR_IN_CONTRACT_DESCRIPTION!>returns(null) implies (!this@case_1)<!> }
     return if (!this) null else true
 }

compiler/tests-spec/testData/diagnostics/notLinked/contracts/declarations/contractBuilder/effects/returns/neg/6.fir.kt

@@ -9,7 +9,7 @@ fun Boolean?.case_1(): Boolean {
 }
 
 // TESTCASE NUMBER: 2
-fun <T : Boolean>T?.case_2(): Boolean {
+fun <T : <!FINAL_UPPER_BOUND!>Boolean<!>>T?.case_2(): Boolean {
     contract { <!ERROR_IN_CONTRACT_DESCRIPTION!>returns(true) implies (this@case_2 != null && this@case_2 !is Nothing && this@case_2)<!> }
     return this != null && this !is Nothing && this
 }

compiler/tests-spec/testData/diagnostics/notLinked/contracts/declarations/contractBuilder/effects/returns/neg/7.fir.kt

@@ -10,7 +10,7 @@ fun <T : Number?> T.case_1() {
 }
 
 // TESTCASE NUMBER: 2
-fun <T : Number, K : String> T?.case_2(value_1: K?) {
+fun <T : Number, K : <!FINAL_UPPER_BOUND!>String<!>> T?.case_2(value_1: K?) {
     contract { returns() implies (this@case_2 is T && value_1 is K) }
     if (!(this@case_2 is T && value_1 is K)) throw Exception()
 }