Remove "return struct" in rule implementation of some Bazel tests (#2)

This makes the affected tests compatible with --incompatible_disallow_struct_provider_syntax

Progress toward #7347.

RELNOTES: None.
PiperOrigin-RevId: 244210656
diff --git a/src/test/java/com/google/devtools/build/lib/analysis/CircularDependencyTest.java b/src/test/java/com/google/devtools/build/lib/analysis/CircularDependencyTest.java
index 1e179b2..c87b315 100644
--- a/src/test/java/com/google/devtools/build/lib/analysis/CircularDependencyTest.java
+++ b/src/test/java/com/google/devtools/build/lib/analysis/CircularDependencyTest.java
@@ -213,9 +213,10 @@
         "plain(name = 'c')",
         "plain(name = 'aspectdep', aspect_deps = ['a'])");
 
-    scratch.file("x/x.bzl",
+    scratch.file(
+        "x/x.bzl",
         "def _impl(ctx):",
-        "    return struct()",
+        "    return []",
         "",
         "rule_aspect = aspect(",
         "    implementation = _impl,",