Use art::GetAndroidRoot instead of ANDROID_HOST_OUT in art::CommonArtTestImpl.

Do not use the environment variable ANDROID_HOST_OUT to find the
Android Root in art::CommonArtTestImpl; rely on art::GetAndroidRoot
instead.

Test: m test-art-host-gtest
Change-Id: I89fc9288164b57bc3f6542864cece312b6df2fd1
diff --git a/libartbase/base/common_art_test.cc b/libartbase/base/common_art_test.cc
index afdb733..ccaa90f 100644
--- a/libartbase/base/common_art_test.cc
+++ b/libartbase/base/common_art_test.cc
@@ -322,14 +322,7 @@
 }
 
 static std::string GetDexFileName(const std::string& jar_prefix, bool host) {
-  std::string path;
-  if (host) {
-    const char* host_dir = getenv("ANDROID_HOST_OUT");
-    CHECK(host_dir != nullptr);
-    path = host_dir;
-  } else {
-    path = GetAndroidRoot();
-  }
+  std::string path = GetAndroidRoot();
 
   std::string suffix = host
       ? "-hostdex"                 // The host version.
@@ -415,8 +408,7 @@
   CHECK(name != nullptr);
   std::string filename;
   if (IsHost()) {
-    filename += getenv("ANDROID_HOST_OUT");
-    filename += "/framework/";
+    filename += GetAndroidRoot() + "/framework/";
   } else {
     filename += ART_TARGET_NATIVETEST_DIR_STRING;
   }
@@ -466,9 +458,8 @@
 
   std::string location;
   if (IsHost()) {
-    const char* host_dir = getenv("ANDROID_HOST_OUT");
-    CHECK(host_dir != nullptr);
-    location = StringPrintf("%s/framework/core.%s", host_dir, suffix);
+    std::string host_dir = GetAndroidRoot();
+    location = StringPrintf("%s/framework/core.%s", host_dir.c_str(), suffix);
   } else {
     location = StringPrintf("/data/art-test/core.%s", suffix);
   }