[llvm] [MIRLexer][RISCV] Eat a space after the Machine comment (PR #115365)

[Matt Arsenault via llvm-commits]

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@@ -0,0 +1,28 @@
+# NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py UTC_ARGS: --version 5
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arsenm wrote:

test belongs in test/CodeGen/MIR 

https://github.com/llvm/llvm-project/pull/115365