[llvm] [mlir] [CMake] add `SKIP` to `add_lit_testsuites` (PR #157176)

[Mehdi Amini via llvm-commits]

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@@ -247,4 +247,5 @@ add_lit_testsuite(check-mlir "Running the MLIR regression tests"
 
 add_lit_testsuites(MLIR ${CMAKE_CURRENT_SOURCE_DIR}
   DEPENDS ${MLIR_TEST_DEPENDS}
+  SKIP python
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joker-eph wrote:

> nothing? 

I mean surely this line is added for having an effect, otherwise we can just remove it right?

>  so no subdirs will be skipped.

I get that, I just don't quite figure what is the effect of skipping it. Can you describe a command I can run and what I should observe before and after?

https://github.com/llvm/llvm-project/pull/157176