[JS IR] Support setting custom module name (= unique name)

Required for #KT-36721.

compiler/cli/cli-common/src/org/jetbrains/kotlin/cli/common/arguments/K2JSCompilerArguments.kt

@@ -128,6 +128,13 @@ class K2JSCompilerArguments : CommonCompilerArguments() {
     @Argument(value = "-Xir-only", description = "Disables pre-IR backend")
     var irOnly: Boolean by FreezableVar(false)
 
+    @Argument(
+        value = "-Xir-module-name",
+        valueDescription = "<name>",
+        description = "Specify a compilation module name for IR backend"
+    )
+    var irModuleName: String? by NullableStringFreezableVar(null)
+
     @Argument(
         value = "-Xinclude",
         valueDescription = "<path>",

compiler/cli/cli-js/src/org/jetbrains/kotlin/cli/js/K2JsIrCompiler.kt

@@ -149,7 +149,10 @@ class K2JsIrCompiler : CLICompiler<K2JSCompilerArguments>() {
 
         val outputFile = File(outputFilePath)
 
-        configurationJs.put(CommonConfigurationKeys.MODULE_NAME, FileUtil.getNameWithoutExtension(outputFile))
+        configurationJs.put(
+            CommonConfigurationKeys.MODULE_NAME,
+            arguments.irModuleName ?: FileUtil.getNameWithoutExtension(outputFile)
+        )
 
         // TODO: in this method at least 3 different compiler configurations are used (original, env.configuration, jsConfig.configuration)
         // Such situation seems a bit buggy...

compiler/testData/cli/js/jsExtraHelp.out

@@ -9,6 +9,7 @@ where advanced options include:
   -Xir-dce-driven            Perform a more experimental faster dead code elimination
   -Xir-dce-print-reachability-info
                              Print declarations' reachability info to stdout during performing DCE
+  -Xir-module-name=<name>    Specify a compilation module name for IR backend
   -Xir-only                  Disables pre-IR backend
   -Xir-produce-js            Generates JS file using IR backend. Also disables pre-IR backend
   -Xir-produce-klib-dir      Generate unpacked KLIB into parent directory of output JS file.