[FIR] Unconditionally enable BooleanElvisBoundSmartCasts feature in K2

^KT-54694 Fixed
^KT-26357

compiler/testData/diagnostics/tests/smartCasts/elvis/basicOff.fir.kt

@@ -0,0 +1,50 @@
+// !LANGUAGE: -BooleanElvisBoundSmartCasts
+
+interface Order {
+    val expired: Boolean?
+
+    fun notExpired(): Boolean
+
+    fun doSomething()
+}
+
+fun foo(o: Any) {
+    val order = o as? Order
+    if (order?.expired ?: false) {
+        order.doSomething()
+    }
+    else {
+
+    }
+    if (order?.notExpired() ?: false) {
+        order.doSomething()
+    }
+}
+
+fun bar(o: Any) {
+    val order = o as? Order
+    if (order?.expired ?: true) {
+
+    }
+    else {
+        order<!UNNECESSARY_NOT_NULL_ASSERTION!>!!<!>.doSomething()
+    }
+    if (order?.notExpired() ?: true) {
+
+    }
+    else {
+        order<!UNNECESSARY_NOT_NULL_ASSERTION!>!!<!>.doSomething()
+    }
+}
+
+fun baz(o: Boolean?) {
+    if (o ?: false) {
+        o.hashCode()
+    }
+    if (o ?: true) {
+
+    }
+    else {
+        o.hashCode()
+    }
+}

compiler/testData/diagnostics/tests/smartCasts/elvis/basicOff.kt

@@ -1,4 +1,3 @@
-// FIR_IDENTICAL
 // !LANGUAGE: -BooleanElvisBoundSmartCasts
 
 interface Order {
@@ -48,4 +47,4 @@ fun baz(o: Boolean?) {
     else {
         o<!UNSAFE_CALL!>.<!>hashCode()
     }
-}
+}