Expose TestAPIs needed by GtsOsTestCases

Test: atest GtsOsTestCases on pi-dev:taimen and oc-mr1:sailfish
Bug: 77497338
Change-Id: I5de976991a857bfbed2faa943822af542601fa8b
diff --git a/core/java/android/os/Environment.java b/core/java/android/os/Environment.java
index 03203d0..213260f 100644
--- a/core/java/android/os/Environment.java
+++ b/core/java/android/os/Environment.java
@@ -16,6 +16,7 @@
 
 package android.os;
 
+import android.annotation.TestApi;
 import android.app.admin.DevicePolicyManager;
 import android.content.Context;
 import android.os.storage.StorageManager;
@@ -1033,6 +1034,7 @@
      *
      * @hide
      */
+    @TestApi
     public static File buildPath(File base, String... segments) {
         File cur = base;
         for (String segment : segments) {