Replace test usages of DigestHashFunction#getDefaultUnchecked and implicit DigestHashFunction#getDefault calls by the actual default hash function. Also remove a bunch of unnecessary Clock injections.

PiperOrigin-RevId: 330572846
diff --git a/src/test/java/com/google/devtools/build/lib/skyframe/PackageFunctionTest.java b/src/test/java/com/google/devtools/build/lib/skyframe/PackageFunctionTest.java
index 1ae670a..c0837cb 100644
--- a/src/test/java/com/google/devtools/build/lib/skyframe/PackageFunctionTest.java
+++ b/src/test/java/com/google/devtools/build/lib/skyframe/PackageFunctionTest.java
@@ -55,6 +55,7 @@
 import com.google.devtools.build.lib.util.ExitCode;
 import com.google.devtools.build.lib.util.Pair;
 import com.google.devtools.build.lib.util.io.TimestampGranularityMonitor;
+import com.google.devtools.build.lib.vfs.DigestHashFunction;
 import com.google.devtools.build.lib.vfs.Dirent;
 import com.google.devtools.build.lib.vfs.FileStatus;
 import com.google.devtools.build.lib.vfs.FileSystem;
@@ -1600,7 +1601,7 @@
     private final Map<Path, IOException> pathsToErrorOnGetInputStream = Maps.newHashMap();
 
     public CustomInMemoryFs(ManualClock manualClock) {
-      super(manualClock);
+      super(manualClock, DigestHashFunction.SHA256);
     }
 
     public void stubStat(Path path, @Nullable FileStatus stubbedResult) {