Add basic FIR -> IR converter with a set of text tests

Tests duplicate IrTextTestCaseGenerated
#KT-24065 Fixed

compiler/fir/tree/src/org/jetbrains/kotlin/fir/expressions/FirOperation.kt

@@ -41,5 +41,7 @@ enum class FirOperation(val operator: String = "???") {
         val BOOLEANS: Set<FirOperation> = EnumSet.of(
             EQ, NOT_EQ, IDENTITY, NOT_IDENTITY, LT, GT, LT_EQ, GT_EQ, IS, NOT_IS
         )
+
+        val COMPARISONS: Set<FirOperation> = EnumSet.of(LT, GT, LT_EQ, GT_EQ)
     }
 }

compiler/fir/tree/src/org/jetbrains/kotlin/fir/symbols/impl/FirFunctionSymbol.kt

@@ -11,7 +11,9 @@ import org.jetbrains.kotlin.fir.types.ConeKotlinType
 
 class FirFunctionSymbol(
     override val callableId: CallableId,
-    val isFakeOverride: Boolean = false
+    val isFakeOverride: Boolean = false,
+    // Actual for fake override only
+    val overriddenSymbol: FirFunctionSymbol? = null
 ) : ConeFunctionSymbol, FirCallableSymbol() {
     override val parameters: List<ConeKotlinType>
         get() = emptyList()

compiler/fir/tree/src/org/jetbrains/kotlin/fir/types/impl/FirImplicitBuiltinTypeRef.kt

@@ -57,3 +57,9 @@ class FirImplicitBooleanTypeRef(
     session: FirSession,
     psi: PsiElement?
 ) : FirImplicitBuiltinTypeRef(session, psi, StandardClassIds.Boolean)
+
+class FirImplicitNothingTypeRef(
+    session: FirSession,
+    psi: PsiElement?
+) : FirImplicitBuiltinTypeRef(session, psi, StandardClassIds.Nothing)
+