[libc-tests] Remove deprecated "system-temp" instances and replace them with "isolated-temp"

Bug: 25092
Change-Id: I29680eeee21a3b068bddb70fcced50d70ff48037
diff --git a/meta/libc-tests-broken.cmx b/meta/libc-tests-broken.cmx
index 5cf9cbb..0a00ba0 100644
--- a/meta/libc-tests-broken.cmx
+++ b/meta/libc-tests-broken.cmx
@@ -4,7 +4,7 @@
     },
     "sandbox": {
         "features": [
-            "system-temp",
+            "isolated-temp",
             "deprecated-ambient-replace-as-executable"
         ]
     }
diff --git a/meta/libc-tests.cmx b/meta/libc-tests.cmx
index fd3bcae..896aa45 100644
--- a/meta/libc-tests.cmx
+++ b/meta/libc-tests.cmx
@@ -4,7 +4,7 @@
     },
     "sandbox": {
         "features": [
-            "system-temp",
+            "isolated-temp",
             "deprecated-ambient-replace-as-executable"
         ]
     }