Enable junit4 use in Debian builds (main)

Using @meteorcloudy's method to enable use of native Debian libraries for junit4

Related #12755.

PiperOrigin-RevId: 350104824
diff --git a/tools/distributions/debian/debian_java.BUILD b/tools/distributions/debian/debian_java.BUILD
index 1d0544e..92d863f 100644
--- a/tools/distributions/debian/debian_java.BUILD
+++ b/tools/distributions/debian/debian_java.BUILD
@@ -449,3 +449,12 @@
         "grpc-stub.jar",
     ],
 )
+
+# junit4
+java_import(
+    name = "junit4",
+    jars = [
+        "hamcrest-core.jar",
+        "junit4.jar",
+    ],
+)