[lit] Apply aa71680's fix to an additional test

Seen at
<https://lab.llvm.org/buildbot/#/builders/216/builds/27538/steps/7/logs/FAIL__lit___shtest-external-shell-kill_py>.

llvm/utils/lit/tests/lit.cfg

@@ -73,6 +73,16 @@ config.substitutions.append(
 )
 config.substitutions.append(("%{python}", '"%s"' % (sys.executable)))
 
+# This diagnostic sometimes appears in windows when using bash as an external
+# shell.  Ignore it in lit's output where we need to strictly check only the
+# relevant output.
+config.substitutions.append(
+    (
+        "%{filter-lit}",
+        "grep -v 'bash.exe: warning: could not find /tmp, please create!'",
+    )
+)
+
 # Enable coverage.py reporting, assuming the coverage module has been installed
 # and sitecustomize.py in the virtualenv has been modified appropriately.
 if lit_config.params.get("check-coverage", None):

llvm/utils/lit/tests/shtest-external-shell-kill.py

@@ -20,7 +20,7 @@
 # The last FileCheck directive below checks that the debugging commands for the
 # above RUN line are not killed and do execute at the right time.
 
-# RUN: %{lit} -a %{inputs}/shtest-external-shell-kill | FileCheck %s
+# RUN: %{lit} -a %{inputs}/shtest-external-shell-kill | %{filter-lit} | FileCheck %s
 # END.
 
 #       CHECK: Command Output (stdout):

llvm/utils/lit/tests/shtest-run-at-line.py

@@ -1,15 +1,9 @@
 # Check that -a/-v/-vv makes the line number of the failing RUN command clear.
 
 
-# This diagnostic sometimes appears in windows when using bash as an external
-# shell.  Ignore it so we can strictly check the relevant output.
-#
-# DEFINE: %{filter} = \
-# DEFINE:   grep -v 'bash.exe: warning: could not find /tmp, please create!'
-
-# RUN: not %{lit} -a %{inputs}/shtest-run-at-line | %{filter} | FileCheck %s
-# RUN: not %{lit} -v %{inputs}/shtest-run-at-line | %{filter} | FileCheck %s
-# RUN: not %{lit} -vv %{inputs}/shtest-run-at-line | %{filter} | FileCheck %s
+# RUN: not %{lit} -a %{inputs}/shtest-run-at-line | %{filter-lit} | FileCheck %s
+# RUN: not %{lit} -v %{inputs}/shtest-run-at-line | %{filter-lit} | FileCheck %s
+# RUN: not %{lit} -vv %{inputs}/shtest-run-at-line | %{filter-lit} | FileCheck %s
 # END.