Remove unused split() method.

Part of #7814.

Closes #7815.

PiperOrigin-RevId: 239811685
diff --git a/src/main/java/com/google/devtools/build/lib/analysis/config/TransitionResolver.java b/src/main/java/com/google/devtools/build/lib/analysis/config/TransitionResolver.java
index d9345e0..ae22a85 100644
--- a/src/main/java/com/google/devtools/build/lib/analysis/config/TransitionResolver.java
+++ b/src/main/java/com/google/devtools/build/lib/analysis/config/TransitionResolver.java
@@ -20,7 +20,6 @@
 import com.google.devtools.build.lib.analysis.config.transitions.NoTransition;
 import com.google.devtools.build.lib.analysis.config.transitions.NullTransition;
 import com.google.devtools.build.lib.analysis.config.transitions.PatchTransition;
-import com.google.devtools.build.lib.analysis.config.transitions.SplitTransition;
 import com.google.devtools.build.lib.packages.Rule;
 import com.google.devtools.build.lib.packages.RuleTransitionFactory;
 import com.google.devtools.build.lib.packages.Target;
@@ -118,16 +117,6 @@
         || transition == HostTransition.INSTANCE);
   }
 
-  /** Applies the given split and composes it after an existing transition. */
-  public static ConfigurationTransition split(
-      ConfigurationTransition currentTransition, SplitTransition split) {
-    Preconditions.checkState(currentTransition != NullTransition.INSTANCE,
-        "cannot apply splits after null transitions (null transitions are expected to be final)");
-    Preconditions.checkState(currentTransition != HostTransition.INSTANCE,
-        "cannot apply splits after host transitions (host transitions are expected to be final)");
-    return composeTransitions(currentTransition, split);
-  }
-
   /**
    * @param currentTransition a pre-existing transition to be composed with
    * @param toTarget target whose associated rule's incoming transition should be applied