[llvm] [lit] Add JSON diffing support to lit (PR #177513)

[Henrik G. Olsson via llvm-commits]

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@@ -0,0 +1,15 @@
+# Check the json-diff builtin command
+
+# RUN: %{lit} -a %{inputs}/shtest-json-diff | FileCheck -match-full-lines %s
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hnrklssn wrote:

This doesn't actually test lit itself, but the `json-diff` utility, so it doesn't need this nested lit invocation. Those tests could just be top-level lit tests.

https://github.com/llvm/llvm-project/pull/177513