Revert^2 "Making CompletableFutureTest as known failure on gcstress debug"

This reverts commit I68d342d26004d85f7ae546c9eeb1034f6f9e430b.

Reason for revert: Test is still failing

Change-Id: I9bceac72497ae440e5448072178973b18eb68834
diff --git a/tools/libcore_gcstress_debug_failures.txt b/tools/libcore_gcstress_debug_failures.txt
index aa5a4f6..4718947 100644
--- a/tools/libcore_gcstress_debug_failures.txt
+++ b/tools/libcore_gcstress_debug_failures.txt
@@ -62,5 +62,13 @@
   names: ["libcore.java.lang.ThreadTest#nativeThreadNames",
           "jsr166.ThreadLocalTest#testGenericITL"
   ]
+},
+{
+  description: "Time-sensitive test fails check of elapsed time with gcstress",
+  result: EXEC_FAILED,
+  bug: 205007075,
+  names: ["jsr166.CompletableFutureTest#testCompleteOnTimeout_completed",
+          "jsr166.CompletableFutureTest#testDelayedExecutor"
+         ]
 }
 ]