merge(3p/absl): subtree merge of Abseil up to e19260f

... notably, this includes Abseil's own StatusOr type, which
conflicted with our implementation (that was taken from TensorFlow).

Change-Id: Ie7d6764b64055caaeb8dc7b6b9d066291e6b538f

third_party/abseil_cpp/absl/random/CMakeLists.txt

@@ -1159,6 +1159,21 @@ absl_cc_library(
     absl::type_traits
 )
 
+# Internal-only target, do not depend on directly.
+absl_cc_test(
+  NAME
+    random_internal_uniform_helper_test
+  SRCS
+    "internal/uniform_helper_test.cc"
+  COPTS
+    ${ABSL_TEST_COPTS}
+  LINKOPTS
+    ${ABSL_DEFAULT_LINKOPTS}
+  DEPS
+    absl::random_internal_uniform_helper
+    gtest_main
+)
+
 # Internal-only target, do not depend on directly.
 absl_cc_test(
   NAME