Fix build break for the simulator versions.

runtime/vm/atomic_test.cc

Index: runtime/vm/atomic_test.cc
diff --git a/runtime/vm/atomic_test.cc b/runtime/vm/atomic_test.cc
index e7e366641f92332e5fdba0e282614a75af891ece..2e327a52235817c8b444046a8b9a1625b3a88b80 100644
--- a/runtime/vm/atomic_test.cc
+++ b/runtime/vm/atomic_test.cc
@@ -32,7 +32,7 @@ UNIT_TEST_CASE(LoadRelaxed) {
 }
 
 
-UNIT_TEST_CASE(CompareAndSwapWord) {
+TEST_CASE(CompareAndSwapWord) {
   uword old_value = 42;
   uword new_value = 100;
   uword result = AtomicOperations::CompareAndSwapWord(
@@ -41,7 +41,7 @@ UNIT_TEST_CASE(CompareAndSwapWord) {
 }
 
 
-UNIT_TEST_CASE(CompareAndSwapUint32) {
+TEST_CASE(CompareAndSwapUint32) {
   uint32_t old_value = 42;
   uint32_t new_value = 100;
   uint32_t result = AtomicOperations::CompareAndSwapUint32(