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

kotlin-native/backend.native/compiler/ir/backend.native/src/org/jetbrains/kotlin/backend/konan/KonanDriver.kt

@@ -172,7 +172,7 @@ class KonanDriver(
             copy(BinaryOptions.objcExportDisableSwiftMemberNameMangling)
             copy(BinaryOptions.objcExportIgnoreInterfaceMethodCollisions)
             copy(KonanConfigKeys.OBJC_GENERICS)
-            copy(CommonConfigurationKeys.USE_IR_FAKE_OVERRIDE_BUILDER)
+            copy(CommonConfigurationKeys.USE_FIR_BASED_FAKE_OVERRIDE_GENERATOR)
         }
 
         // For the second stage, remove already compiled source files from the configuration.