java_tools: explicitly export the .jar files

As these files are used directly outside this external repository,
add an export statement for them. In this way, after the next java_tools
release, bazel itself will be ready for the flip of --incompatible_no_implicit_file_export.

Change-Id: I14aaf369f9db6652611d927cc78dea713ebee5d1
PiperOrigin-RevId: 280607496
diff --git a/tools/jdk/BUILD.java_tools b/tools/jdk/BUILD.java_tools
index 1052b2f..a33e6ff 100644
--- a/tools/jdk/BUILD.java_tools
+++ b/tools/jdk/BUILD.java_tools
@@ -1,4 +1,5 @@
 package(default_visibility = ["//visibility:public"])
+exports_files(glob(["**/*.jar"]))
 
 licenses(["notice"])  # Apache 2.0