libcutils: reimplement system property functions with libbase.

This makes the system property functions available on the host too, and
ensures a consistent view of system properties between libcutils and
libbase, if you have code running on the host that uses both.

Bug: http://b/151789258
Test: treehugger
Change-Id: Ie524a77d0c392d7b23e9d12becbb1bf53c81eac6
diff --git a/libcutils/Android.bp b/libcutils/Android.bp
index d7c83a2..60400c9 100644
--- a/libcutils/Android.bp
+++ b/libcutils/Android.bp
@@ -152,6 +152,7 @@
         "iosched_policy.cpp",
         "load_file.cpp",
         "native_handle.cpp",
+        "properties.cpp",
         "record_stream.cpp",
         "strlcpy.c",
         "threads.cpp",
@@ -187,7 +188,6 @@
                 "fs_config.cpp",
                 "klog.cpp",
                 "partition_utils.cpp",
-                "properties.cpp",
                 "qtaguid.cpp",
                 "trace-dev.cpp",
                 "uevent.cpp",
@@ -268,6 +268,7 @@
     name: "libcutils_test_default",
     srcs: [
         "native_handle_test.cpp",
+        "properties_test.cpp",
         "sockets_test.cpp",
     ],
 
@@ -280,7 +281,6 @@
                 "fs_config_test.cpp",
                 "memset_test.cpp",
                 "multiuser_test.cpp",
-                "properties_test.cpp",
                 "sched_policy_test.cpp",
                 "str_parms_test.cpp",
                 "trace-dev_test.cpp",