feat(3p/absl): import StatusOr from tensorflow

Additionally, add tests for the macros. A future CL will enable the tests in CI.

Change-Id: Id4445a1aa65bf6751b87606f37654f3fc6d20efc
Tested-By: kanepyork <rikingcoding@gmail.com>
Reviewed-on: https://cl.tvl.fyi/c/depot/+/1274
Reviewed-by: tazjin <mail@tazj.in>
Reviewed-by: glittershark <grfn@gws.fyi>
Tested-by: BuildkiteCI

third_party/abseil_cpp/absl/status/CMakeLists.txt

@@ -39,6 +39,24 @@ absl_cc_library(
   PUBLIC
 )
 
+absl_cc_library(
+  NAME
+    statusor
+  HDRS
+    "statusor.h"
+  SRCS
+    "statusor.cc"
+    "statusor_internals.h"
+  COPTS
+    ${ABSL_DEFAULT_COPTS}
+  DEPS
+    absl::status
+    absl::atomic_hook
+    absl::raw_logging_internal
+    absl::strings
+  PUBLIC
+)
+
 absl_cc_test(
   NAME
     status_test
@@ -51,3 +69,17 @@ absl_cc_test(
     absl::strings
     gmock_main
 )
+
+absl_cc_test(
+  NAME
+    statusor_test
+  SRCS
+   "statusor_test.cc"
+  COPTS
+    ${ABSL_TEST_COPTS}
+  DEPS
+    absl::status
+    absl::statusor
+    absl::strings
+    gmock_main
+)