Remove outdated --experimental_starlark_config_transitions from Bazel.

As of 6619d77, this was already a no-op.

PiperOrigin-RevId: 365044031

Author: gregestren

src/main/java/com/google/devtools/build/lib/packages/semantics/BuildLanguageOptions.java

@@ -178,15 +178,6 @@ public class BuildLanguageOptions extends OptionsBase implements Serializable {
               + "debugging.")
   public boolean experimentalPlatformsApi;
 
-  @Option(
-      name = "experimental_starlark_config_transitions",
-      defaultValue = "true",
-      documentationCategory = OptionDocumentationCategory.UNDOCUMENTED,
-      effectTags = {OptionEffectTag.NO_OP},
-      metadataTags = {OptionMetadataTag.DEPRECATED},
-      help = "No-op: to be removed as soon once all references are gone")
-  public boolean experimentalStarlarkConfigTransitions;
-
   @Option(
       name = "experimental_cc_shared_library",
       defaultValue = "false",