Fixes external storage path for SensorCtsHelper getSensorTestDirectory()

Uses getExternalStorageDirectory() instead of System.getenv("EXTERNAL_STORAGE")
getExternalStorageDirectory() returns external sdcard path if available else returns
path to emulated external storage and the correct user path unlike
System.getenv("EXTERNAL_STORAGE") that always returns emulated storage path.

Bug: 122847403
Test:  Run test module CtsSensorTestCases on Pixel/AAE platform.
Change-Id: I5bf27940812575b094f18974b0b41ffa5be815f6
diff --git a/tests/sensor/src/android/hardware/cts/helpers/SensorCtsHelper.java b/tests/sensor/src/android/hardware/cts/helpers/SensorCtsHelper.java
index bbe2006..1edf617 100644
--- a/tests/sensor/src/android/hardware/cts/helpers/SensorCtsHelper.java
+++ b/tests/sensor/src/android/hardware/cts/helpers/SensorCtsHelper.java
@@ -16,6 +16,7 @@
 package android.hardware.cts.helpers;
 
 import android.hardware.Sensor;
+import android.os.Environment;
 import android.util.Log;
 import java.io.File;
 import java.io.IOException;
@@ -255,7 +256,7 @@
      * @return A {@link File} representing a root directory to store sensor tests data.
      */
     public static File getSensorTestDataDirectory() throws IOException {
-        File dataDirectory = new File(System.getenv("EXTERNAL_STORAGE"), "sensorTests/");
+        File dataDirectory = new File(Environment.getExternalStorageDirectory(), "sensorTests/");
         return createDirectoryStructure(dataDirectory);
     }