Fir2Ir: enable IR-based fake override builder

Invert the logic of IR/FIR2IR-based generators: change the CLI argument
to -Xuse-fir-fake-override-builder, test directive to
USE_FIR_BASED_FAKE_OVERRIDE_GENERATOR, etc.

The changes in test data caused by using IR fake override builder by
default are in the subsequent commit.

 #KT-61514

compiler/testData/cli/js/jsExtraHelp.out

@@ -137,10 +137,11 @@ where advanced options include:
                              Eliminate builder inference restrictions, for example by allowing type variables to be returned from builder inference calls.
   -Xuse-fir-extended-checkers Use extended analysis mode based on the frontend IR.
                              Warning: This feature is not yet production-ready.
+  -Xuse-fir-fake-override-builder
+                             Generate all fake overrides via FIR2IR instead of IR, i.e. revert to behavior before KT-61514 was resolved.
   -Xuse-fir-ic               Compile using frontend IR internal incremental compilation.
                              Warning: This feature is not yet production-ready.
   -Xuse-fir-lt               Compile using the LightTree parser with the frontend IR.
-  -Xuse-ir-fake-override-builder Generate fake overrides via IR. See KT-61514
   -Xuse-k2                   Compile using the experimental K2 compiler pipeline. No compatibility guarantees are provided yet.
   -Xverbose-phases           Be verbose while performing the given backend phases.
 

compiler/testData/cli/jvm/extraHelp.out

@@ -229,10 +229,11 @@ where advanced options include:
                              Eliminate builder inference restrictions, for example by allowing type variables to be returned from builder inference calls.
   -Xuse-fir-extended-checkers Use extended analysis mode based on the frontend IR.
                              Warning: This feature is not yet production-ready.
+  -Xuse-fir-fake-override-builder
+                             Generate all fake overrides via FIR2IR instead of IR, i.e. revert to behavior before KT-61514 was resolved.
   -Xuse-fir-ic               Compile using frontend IR internal incremental compilation.
                              Warning: This feature is not yet production-ready.
   -Xuse-fir-lt               Compile using the LightTree parser with the frontend IR.
-  -Xuse-ir-fake-override-builder Generate fake overrides via IR. See KT-61514
   -Xuse-k2                   Compile using the experimental K2 compiler pipeline. No compatibility guarantees are provided yet.
   -Xverbose-phases           Be verbose while performing the given backend phases.
 

compiler/testData/ir/irText/declarations/fakeOverrideModality.kt

@@ -1,5 +1,4 @@
 // FIR_IDENTICAL
-// ENABLE_IR_FAKE_OVERRIDE_GENERATION
 // TARGET_BACKEND: JVM
 
 open class Base

compiler/testData/ir/irText/declarations/internalStdlibOverride.kt

@@ -1,6 +1,5 @@
 // FIR_IDENTICAL
 // WITH_STDLIB
-// ENABLE_IR_FAKE_OVERRIDE_GENERATION
 // KT-64692
 
 // test data differs - no getOrDefault in AbstractMap for non-jvm.
@@ -11,4 +10,4 @@ class MyMap : AbstractMap<Int, Int>() {
 
     // clash with stdlib internal function
     fun containsEntry(entry: Map.Entry<*, *>?) = false
-}
+}

compiler/testData/ir/irText/declarations/kt65236.kt

@@ -1,5 +1,4 @@
 // FIR_IDENTICAL
-// ENABLE_IR_FAKE_OVERRIDE_GENERATION
 // TARGET_BACKEND: JVM
 
 // FILE: J.java
@@ -29,4 +28,4 @@ class E : D() {
 
 fun foo(x : I) {
     x.foo()
-}
+}

compiler/testData/ir/irText/declarations/kt65432.kt

@@ -1,10 +1,7 @@
-// WITH_STDLIB
-// ENABLE_IR_FAKE_OVERRIDE_GENERATION
-// SEPARATE_SIGNATURE_DUMP_FOR_K2
-// ^ Value parameters in fake overrides generated by K1 and K2 are different
-
 // WITH_REFLECT
 // TARGET_BACKEND: JVM_IR
+// SEPARATE_SIGNATURE_DUMP_FOR_K2
+// ^ Value parameters in fake overrides generated by K1 and K2 are different
 
 // FILE: Java1.java
 public class Java1 extends KotlinClass { }
@@ -14,4 +11,4 @@ import java.util.ArrayList
 
 class A : Java1()
 
-open class KotlinClass : ArrayList<Int>()
+open class KotlinClass : ArrayList<Int>()

compiler/testData/ir/irText/fakeOverrides/annotatedTypeParameter.kt

@@ -1,7 +1,6 @@
 // TARGET_BACKEND: JVM_IR
 // WITH_STDLIB
 // FULL_JDK
-// ENABLE_IR_FAKE_OVERRIDE_GENERATION
 // SEPARATE_SIGNATURE_DUMP_FOR_K2
 // ISSUE: KT-65302
 

compiler/testData/ir/irText/fakeOverrides/intersectionWithJava.kt

@@ -1,5 +1,4 @@
 // TARGET_BACKEND: JVM
-// ENABLE_IR_FAKE_OVERRIDE_GENERATION
 // ISSUE: KT-65207
 
 // FILE: Java1.java

compiler/testData/ir/irText/fakeOverrides/intersectionWithRawType.kt

@@ -1,5 +1,4 @@
 // FIR_IDENTICAL
-// ENABLE_IR_FAKE_OVERRIDE_GENERATION
 // TARGET_BACKEND: JVM_IR
 // ISSUE: KT-65493