bazel syntax: reverse syntax->events dependency

Details:
- Location has moved to syntax: it represents a location in a Starlark source file.
- StarlarkThread.makeDebugPrintHandler has moved to Event.
- The Eventable hack is gone.

This is a breaking API change for Copybara.

PiperOrigin-RevId: 304415517
diff --git a/src/main/java/com/google/devtools/build/lib/analysis/ActionsProvider.java b/src/main/java/com/google/devtools/build/lib/analysis/ActionsProvider.java
index efd0741..fc74dab 100644
--- a/src/main/java/com/google/devtools/build/lib/analysis/ActionsProvider.java
+++ b/src/main/java/com/google/devtools/build/lib/analysis/ActionsProvider.java
@@ -16,11 +16,11 @@
 import com.google.common.collect.ImmutableMap;
 import com.google.devtools.build.lib.actions.ActionAnalysisMetadata;
 import com.google.devtools.build.lib.actions.Artifact;
-import com.google.devtools.build.lib.events.Location;
 import com.google.devtools.build.lib.packages.BuiltinProvider;
 import com.google.devtools.build.lib.packages.SkylarkInfo;
 import com.google.devtools.build.lib.packages.StructImpl;
 import com.google.devtools.build.lib.skylarkbuildapi.ActionsInfoProviderApi;
+import com.google.devtools.build.lib.syntax.Location;
 import com.google.devtools.build.lib.syntax.Starlark;
 import java.util.HashMap;
 import java.util.Map;