aconfig: split aconfig_storage_file crate

Current aconfig_storage_file crate contains two things: 1,
aconfig storage file definition (which is used by aconfig crate for
storage file creation) and 2, flag storage file read api. With this
change, we are splitting 2 into its own crate aconfig_storage_read_api

In the long run, there will be 3 crates for aconfig_storage

1, aconfig_storage_file
It contains aconfig storage file definition, as well as a binary to help
print/dump aconfig storage binary files into some readable format.

2, aconfig_storage_read_api
This crate contains flag read apis. This crate depends on
aconfig_storge_file crate. This crate will be used by codegen.

3, aconfig_storage_write_api
This crate contains flag write apis. This crate depends on
aconfig_storage_file crate. This crate will only be used by aconfig
daemon to update flag values.

Bug: b/321077378
Test: atest aconfig_storage_read_api.test; atest
aconfig_storage_file.test; atest aconfig_storage_read_api.test.rust;
atest aconfig_storage_read_api.test.cpp

Change-Id: Ia6afdc40a45c7c59652fbfd123c2b77bf6666dd9
diff --git a/tools/aconfig/TEST_MAPPING b/tools/aconfig/TEST_MAPPING
index b07596f..26d6172 100644
--- a/tools/aconfig/TEST_MAPPING
+++ b/tools/aconfig/TEST_MAPPING
@@ -70,12 +70,16 @@
   ],
   "postsubmit": [
     {
+      // aconfig_storage_read_api unit tests
+      "name": "aconfig_storage_read_api.test"
+    },
+    {
       // aconfig_storage read api rust integration tests
-      "name": "aconfig_storage.test.rust"
+      "name": "aconfig_storage_read_api.test.rust"
     },
     {
       // aconfig_storage read api cpp integration tests
-      "name": "aconfig_storage.test.cpp"
+      "name": "aconfig_storage_read_api.test.cpp"
     },
     {
       // aflags CLI unit tests