Kotlin: address PR review feedback

Align Kotlin 2.4 registrar plugin id with command-line processor, drop unused registrar state, fix the function-reference explanatory comment, and remove 1.x extractor targets from VERSIONS.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

MODULE.bazel

@@ -237,9 +237,6 @@ use_repo(
     kotlin_extractor_deps,
     "codeql_kotlin_defaults",
     "codeql_kotlin_embeddable",
-    "kotlin-compiler-1.8.0",
-    "kotlin-compiler-1.9.0-Beta",
-    "kotlin-compiler-1.9.20-Beta",
     "kotlin-compiler-2.0.0-RC1",
     "kotlin-compiler-2.0.20-Beta2",
     "kotlin-compiler-2.1.0-Beta1",
@@ -249,9 +246,6 @@ use_repo(
     "kotlin-compiler-2.3.0",
     "kotlin-compiler-2.3.20",
     "kotlin-compiler-2.4.0",
-    "kotlin-compiler-embeddable-1.8.0",
-    "kotlin-compiler-embeddable-1.9.0-Beta",
-    "kotlin-compiler-embeddable-1.9.20-Beta",
     "kotlin-compiler-embeddable-2.0.0-RC1",
     "kotlin-compiler-embeddable-2.0.20-Beta2",
     "kotlin-compiler-embeddable-2.1.0-Beta1",
@@ -261,9 +255,6 @@ use_repo(
     "kotlin-compiler-embeddable-2.3.0",
     "kotlin-compiler-embeddable-2.3.20",
     "kotlin-compiler-embeddable-2.4.0",
-    "kotlin-stdlib-1.8.0",
-    "kotlin-stdlib-1.9.0-Beta",
-    "kotlin-stdlib-1.9.20-Beta",
     "kotlin-stdlib-2.0.0-RC1",
     "kotlin-stdlib-2.0.20-Beta2",
     "kotlin-stdlib-2.1.0-Beta1",

java/kotlin-extractor/src/main/kotlin/KotlinFileExtractor.kt

@@ -7808,7 +7808,7 @@ open class KotlinFileExtractor(
              *   constructor(dispatchReceiver: TD, extensionReceiver: TE) {
              *       super()
              *       this.dispatchReceiver = dispatchReceiver
-             *       this.codeQlExtensionReceiver = extensionReceiver
+             *       this.extensionReceiver = extensionReceiver
              *   }
              *   fun invoke(a0:T0, a1:T1, ... aI: TI): R { return this.dispatchReceiver.FN(a0,a1,...,aI) }                       OR
              *   fun invoke(       a1:T1, ... aI: TI): R { return this.dispatchReceiver.FN(this.dispatchReceiver,a1,...,aI) }    OR

java/kotlin-extractor/src/main/kotlin/utils/versions/v_2_4_0/Kotlin2ComponentRegistrar.kt

@@ -15,7 +15,7 @@ abstract class Kotlin2ComponentRegistrar : CompilerPluginRegistrar(), ComponentR
         get() = true
 
     override val pluginId: String
-        get() = "com.github.codeql.kotlin-extractor"
+        get() = "kotlin-extractor"
 
     // ComponentRegistrar implementation (legacy path, still called by Kotlin compiler)
     override fun registerProjectComponents(
@@ -28,7 +28,6 @@ abstract class Kotlin2ComponentRegistrar : CompilerPluginRegistrar(), ComponentR
     }
 
     private var extensionStorage: CompilerPluginRegistrar.ExtensionStorage? = null
-    private var registeredExtension: IrGenerationExtension? = null
 
     override fun ExtensionStorage.registerExtensions(configuration: CompilerConfiguration) {
         this@Kotlin2ComponentRegistrar.extensionStorage = this

java/kotlin-extractor/versions.bzl

@@ -1,8 +1,5 @@
 # when updating this list, `bazel mod tidy` should be run from `codeql` to update `MODULE.bazel`
 VERSIONS = [
-    "1.8.0",
-    "1.9.0-Beta",
-    "1.9.20-Beta",
     "2.0.0-RC1",
     "2.0.20-Beta2",
     "2.1.0-Beta1",
@@ -24,8 +21,6 @@ def version_less(lhs, rhs):
 
 def get_language_version(version):
     major, minor, _ = _version_to_tuple(version)
-    if major == 1:
-        return "2.0"
     return "%s.%s" % (major, minor)
 
 def _basename(path):