[llvm] [llvm][docs] Small improvements to llvm-test-suite doc (PR #139083)

[David Spickett via llvm-commits]

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@@ -85,9 +86,10 @@ MicroBenchmarks/XRay microbenchmarks, you need to add `compiler-rt` to your
    PASS: test-suite :: MultiSource/Applications/ALAC/encode/alacconvert-encode.test (2 of 474)
    ...
    ```
-**NOTE!** even in the case you only want to get the compile-time results(code size, llvm stats etc),
-you need to run the test with the above `llvm-lit` command. In that case, the *results.json* file will
-contain compile-time metrics.
+**NOTE!** even in the case you only want to get the compile-time results
+(`-DTEST_SUITE_RUN_BENCHMARKS=OFF`, to get code size, llvm stats etc),
+you need to run the test with the above `llvm-lit` command. In that case,
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DavidSpickett wrote:

I've done a version of this, confirmed to render correctly in a local build.

https://github.com/llvm/llvm-project/pull/139083