Use Bazel Preconditions variant which avoids varargs array creation

Reduces garbage.

--
MOS_MIGRATED_REVID=109914243
diff --git a/src/main/java/com/google/devtools/build/lib/actions/Artifact.java b/src/main/java/com/google/devtools/build/lib/actions/Artifact.java
index bdf4639..b358b04 100644
--- a/src/main/java/com/google/devtools/build/lib/actions/Artifact.java
+++ b/src/main/java/com/google/devtools/build/lib/actions/Artifact.java
@@ -18,7 +18,6 @@
 import com.google.common.base.Function;
 import com.google.common.base.Functions;
 import com.google.common.base.Joiner;
-import com.google.common.base.Preconditions;
 import com.google.common.base.Predicate;
 import com.google.common.collect.ImmutableList;
 import com.google.common.collect.Iterables;
@@ -31,6 +30,7 @@
 import com.google.devtools.build.lib.syntax.SkylarkModule;
 import com.google.devtools.build.lib.syntax.SkylarkValue;
 import com.google.devtools.build.lib.util.FileType;
+import com.google.devtools.build.lib.util.Preconditions;
 import com.google.devtools.build.lib.vfs.Path;
 import com.google.devtools.build.lib.vfs.PathFragment;