[llvm] [utils][tests] Adjust timeout-hang.py tolerances (PR #142089)

[Hubert Tong via llvm-commits]

================
@@ -8,20 +8,25 @@
 # throwing an exception. We expect this to fail immediately, rather than
 # timeout.
 
-# DEFINE: %{timeout}=1
+# DEFINE: %{grace_period}=5
+# DEFINE: %{hard_timeout}=15
----------------
hubert-reinterpretcast wrote:

```suggestion
# lit should return immediately once it fails to execute the non-existent file.
# This will take a variable amount of time depending on process scheduling, but
# it should always be significantly less than the hard timeout, which is the
# point where lit would cancel the test.
# DEFINE: %{grace_period}=5
# DEFINE: %{hard_timeout}=15
```

https://github.com/llvm/llvm-project/pull/142089