CMake: Mark absl::cord_test_helpers and absl::spy_hash_state PUBLIC

PiperOrigin-RevId: 478611460
Change-Id: I327dbd1c16a22649e3a25b9ebbc94b48a2fda26f

absl/hash/CMakeLists.txt

@@ -82,6 +82,10 @@ absl_cc_test(
 )
 
 # Internal-only target, do not depend on directly.
+#
+# Note: Even though external code should not depend on this target
+# directly, it must be marked PUBLIC since it is a dependency of
+# hash_testing.
 absl_cc_library(
   NAME
     spy_hash_state
@@ -94,6 +98,7 @@ absl_cc_library(
     absl::strings
     absl::str_format
   TESTONLY
+  PUBLIC
 )
 
 # Internal-only target, do not depend on directly.

absl/strings/CMakeLists.txt

@@ -903,6 +903,7 @@ absl_cc_library(
     absl::cord_internal
     absl::strings
   TESTONLY
+  PUBLIC
 )
 
 # Internal-only target, do not depend on directly.