[llvm] [llvm-lit] Resolve env subcommand required error (PR #98414)

[via llvm-commits]

Harini0924 wrote:

@jh7370 @arichardson I've changed `# CHECK-NOT: {{^[^#]}}` to  `# CHECK-NOT: # error:` for the tests I modified. To maintain consistency across the whole file, should update the other passing tests to use `# CHECK-NOT: # error:` as well.

https://github.com/llvm/llvm-project/pull/98414