[llvm] [lit] Add an option to read an xfail list from a file (PR #163959)

[David Spickett via llvm-commits]

================
@@ -309,13 +309,25 @@ def parse_args():
         help="XFAIL tests with paths in the semicolon separated list",
         default=os.environ.get("LIT_XFAIL", ""),
     )
+    selection_group.add_argument(
+        "--xfail-from-file",
+        metavar="PATH",
+        help="XFAIL tests with paths in the line separated list contained in "
+        "the specified file",
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DavidSpickett wrote:

Maybe reword to split purpose and format:
XFAIL tests whose paths are contained in the specified file. Each path should be newline separated in the file.

https://github.com/llvm/llvm-project/pull/163959