Preemptively use //third_party:guava-failureaccess-jar in

`//src/test/java/com/google/devtools/build/android/desugar:desugar_guava_at_head`.

This is commit 2/5 for
#14942 (comment).

src/test/java/com/google/devtools/build/android/desugar/BUILD

@@ -2094,14 +2094,17 @@ genrule(
     name = "desugar_guava_at_head",
     srcs = [
         "//third_party:guava-jars",
+        "//third_party:guava-failureaccess-jar",
         # Depend on Jacoco runtime in case testdata was built with coverage
         # instrumentation
         "//third_party/java/jacoco:blaze-agent",
         "@bazel_tools//tools/android:android_jar",
     ],
     outs = ["guava_at_head_desugared.jar"],
     cmd = "$(location //src/tools/android/java/com/google/devtools/build/android/desugar:Desugar) " +
-          "-i $(location //third_party:guava-jars) -o $@ " +
+          "-i $(location //third_party:guava-jars) " +
+          "--classpath_entry $(location //third_party:guava-failureaccess-jar) " +
+          "-o $@ " +
           "--bootclasspath_entry $(location @bazel_tools//tools/android:android_jar)",
     tags = ["no_windows"],
     tools = ["//src/tools/android/java/com/google/devtools/build/android/desugar:Desugar"],