Add demo backend to size_test_all_ops

Summary: For pp we can share size_test_all_ops binary running a lowered model and it needs the demo backend.

Reviewed By: dbort

Differential Revision: D47652404

fbshipit-source-id: 563b15e82a94719d0faef729f2dd647c68deafc6

Author: cccclai

runtime/executor/test/targets.bzl

@@ -20,6 +20,7 @@ def define_common_targets():
                 "//executorch/runtime/backend/...",
                 "//executorch/extension/pybindings/...",
                 "//executorch/sdk/runners/...",
+                "//executorch/test/...",
             ],
             # registration of backends is done through a static global
             compiler_flags = ["-Wno-global-constructors"],

test/targets.bzl

@@ -36,6 +36,7 @@ def define_common_targets():
         srcs = SIZE_TEST_SOURCES,
         deps = SIZE_TEST_DEPS + [
             "//executorch/kernels/portable:generated_lib_all_ops",
+            "//executorch/runtime/executor/test:test_backend_compiler_lib",
         ],
         define_static_target = True,
     )