Add cli argumens for FIR "tight" IC and LightTree usage

compiler/cli/cli-common/src/org/jetbrains/kotlin/cli/common/arguments/CommonCompilerArguments.kt

@@ -305,6 +305,18 @@ abstract class CommonCompilerArguments : CommonToolArguments() {
     )
     var useFirExtendedCheckers: Boolean by FreezableVar(false)
 
+    @Argument(
+        value = "-Xuse-fir-ic",
+        description = "Compile using Front-end IR internal incremental compilation cycle. Warning: this feature is far from being production-ready"
+    )
+    var useFirIC: Boolean by FreezableVar(false)
+
+    @Argument(
+        value = "-Xuse-fir-lt",
+        description = "Compile using LightTree parser with Front-end IR. Warning: this feature is far from being production-ready"
+    )
+    var useFirLT: Boolean by FreezableVar(false)
+
     @Argument(
         value = "-Xdisable-ultra-light-classes",
         description = "Do not use the ultra light classes implementation"

compiler/cli/src/org/jetbrains/kotlin/cli/jvm/K2JVMCompiler.kt

@@ -124,7 +124,7 @@ class K2JVMCompiler : CLICompiler<K2JVMCompilerArguments>() {
             val chunk = moduleChunk.modules
             configuration.configureSourceRoots(chunk, buildFile)
 
-            if (configuration.getBoolean(CommonConfigurationKeys.USE_FIR)) {
+            if (configuration.getBoolean(CommonConfigurationKeys.USE_FIR) && arguments.useFirLT /* TODO: consider storing in the configuration instead of using args here directly */) {
                 val projectEnvironment =
                     createProjectEnvironment(configuration, rootDisposable, EnvironmentConfigFiles.JVM_CONFIG_FILES, messageCollector)