Add the system image test to the bazel sandwich

Also make -test.sh files executable, while we wait for a bazel update
that will tell us which FileWrite actions should be executable.

Bug: 297268692
Test: m bazel_sandwich
Change-Id: I60498577ba12813bff8bbdbc1b997ea4addefd17
diff --git a/android/bazel_handler.go b/android/bazel_handler.go
index fda8a22..42ba9b4 100644
--- a/android/bazel_handler.go
+++ b/android/bazel_handler.go
@@ -1382,7 +1382,14 @@
 			WriteFileRuleVerbatim(ctx, out, "")
 		case "FileWrite", "SourceSymlinkManifest":
 			out := PathForBazelOut(ctx, buildStatement.OutputPaths[0])
-			WriteFileRuleVerbatim(ctx, out, buildStatement.FileContents)
+			// TODO(b/297366783) This is a hack to make files from skylib's diff_test executable.
+			// We need to update bazel to have aquery tell us whether a file is supposed to be
+			// executable or not.
+			if strings.HasSuffix(buildStatement.OutputPaths[0], "-test.sh") {
+				WriteExecutableFileRuleVerbatim(ctx, out, buildStatement.FileContents)
+			} else {
+				WriteFileRuleVerbatim(ctx, out, buildStatement.FileContents)
+			}
 		case "SymlinkTree":
 			// build-runfiles arguments are the manifest file and the target directory
 			// where it creates the symlink tree according to this manifest (and then