Rename the expected-output text file in built TradeFed ART run-tests.

Test suite packages (e.g. `android-mts.zip`) flatten tests artifacts
into a single `testcases` directory, therefore each included file must
have a unique name. Have the build system rename every `expected.txt`
file to a unique name when building TradeFed-style ART run-tests.

Test: atest art-run-test-001-HelloWorld
Bug: 147812905
Change-Id: I0d433d0a611cb5214ae366e2c1af214e41c127f0
diff --git a/test/994-breakpoint-line/Android.bp b/test/994-breakpoint-line/Android.bp
index 9cd5018..2accb70 100644
--- a/test/994-breakpoint-line/Android.bp
+++ b/test/994-breakpoint-line/Android.bp
@@ -1,6 +1,19 @@
 // Generated by `regen-test-files`. Do not edit manually.
+
+// Build rules for ART run-test `994-breakpoint-line`.
+
+// Test's Dex code.
 java_test {
     name: "art-run-test-994-breakpoint-line",
     defaults: ["art-run-test-defaults"],
     srcs: ["src/**/*.java"],
+    data: [":art-run-test-994-breakpoint-line-expected"],
+}
+
+// Test's expected output.
+genrule {
+    name: "art-run-test-994-breakpoint-line-expected",
+    out: ["art-run-test-994-breakpoint-line-expected.txt"],
+    srcs: ["expected.txt"],
+    cmd: "cp -f $(in) $(out)",
 }