[llvm] [lit] Add readfile substitution (PR #158441)

[James Henderson via llvm-commits]

================
@@ -0,0 +1,8 @@
+import lit.formats
+
+config.name = "shtest-readfile"
+config.suffixes = [".txt"]
+config.test_format = lit.formats.ShTest(execute_external=False)
+config.test_source_root = None
+config.test_exec_root = None
+config.substitutions.append(("%{python}", '"%s"' % (sys.executable)))
----------------
jh7370 wrote:

Is this needed?

https://github.com/llvm/llvm-project/pull/158441