bazel: Set check backend explicitly

Bug: 350585010
Test: Ran pw presubmit against http://pwrev.dev/219791
Change-Id: I101c636126e5bf1c3ffec738be5f23cac8d9bbfb
Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/quickstart/bazel/+/220911
Lint: Lint 🤖 <android-build-ayeaye@system.gserviceaccount.com>
Reviewed-by: Taylor Cramer <cramertj@google.com>
Commit-Queue: Auto-Submit <auto-submit@pigweed-service-accounts.iam.gserviceaccount.com>
Pigweed-Auto-Submit: Ted Pudlik <tpudlik@google.com>
Presubmit-Verified: CQ Bot Account <pigweed-scoped@luci-project-accounts.iam.gserviceaccount.com>
diff --git a/echo.bzl b/echo.bzl
index 0189f5e..4151508 100644
--- a/echo.bzl
+++ b/echo.bzl
@@ -21,6 +21,8 @@
         "@pigweed//pw_boot:backend": "@pigweed//pw_boot_cortex_m",
         "@pigweed//pw_assert:backend": "@pigweed//pw_assert_basic",
         "@pigweed//pw_assert:backend_impl": "@pigweed//pw_assert_basic:impl",
+        "@pigweed//pw_assert:check_backend": "@pigweed//pw_assert_basic",
+        "@pigweed//pw_assert:check_backend_impl": "@pigweed//pw_assert_basic:impl",
         "@pigweed//pw_log:backend": "@pigweed//pw_log_basic",
         "@pigweed//pw_log:backend_impl": "@pigweed//pw_log_basic:impl",
         "@pigweed//pw_sys_io:backend": "@pigweed//pw_sys_io_baremetal_stm32f429",
@@ -34,6 +36,8 @@
         "@pigweed//pw_boot:backend",
         "@pigweed//pw_assert:backend",
         "@pigweed//pw_assert:backend_impl",
+        "@pigweed//pw_assert:check_backend",
+        "@pigweed//pw_assert:check_backend_impl",
         "@pigweed//pw_log:backend",
         "@pigweed//pw_log:backend_impl",
         "@pigweed//pw_sys_io:backend",
diff --git a/src/BUILD.bazel b/src/BUILD.bazel
index aee40f8..8ec1218 100644
--- a/src/BUILD.bazel
+++ b/src/BUILD.bazel
@@ -29,6 +29,8 @@
     }),
     deps = [
         "@pigweed//pw_assert:backend_impl",
+        "@pigweed//pw_assert:check_backend_impl",
+        "@pigweed//pw_assert:assert_backend_impl",
         "@pigweed//pw_boot",
         "@pigweed//pw_sys_io",
     ] + select({