Move isolated test runner out of bionic.

Use a global gtest isolation runner rather than the custom one in
bionic.

Test: Ran all unit tests and verified same behavior before and after.

Change-Id: I24a7cf17cf8e018d0f51969c64b53ce9059cc779
diff --git a/tests/cfi_test.cpp b/tests/cfi_test.cpp
index 5e2518f..e155e1a 100644
--- a/tests/cfi_test.cpp
+++ b/tests/cfi_test.cpp
@@ -135,7 +135,7 @@
 // cfi_test_helper exports __cfi_check, which triggers CFI initialization at startup.
 TEST(cfi_test, early_init) {
 #if defined(__BIONIC__)
-  std::string helper = get_testlib_root() + "/cfi_test_helper/cfi_test_helper";
+  std::string helper = GetTestlibRoot() + "/cfi_test_helper/cfi_test_helper";
   chmod(helper.c_str(), 0755); // TODO: "x" lost in CTS, b/34945607
   ExecTestHelper eth;
   eth.SetArgs({ helper.c_str(), nullptr });
@@ -147,7 +147,7 @@
 // at startup.
 TEST(cfi_test, early_init2) {
 #if defined(__BIONIC__)
-  std::string helper = get_testlib_root() + "/cfi_test_helper2/cfi_test_helper2";
+  std::string helper = GetTestlibRoot() + "/cfi_test_helper2/cfi_test_helper2";
   chmod(helper.c_str(), 0755); // TODO: "x" lost in CTS, b/34945607
   ExecTestHelper eth;
   eth.SetArgs({ helper.c_str(), nullptr });