Fix MLIR default pipeline

[joeycarter]

Context: There was a bug when running the new catalyst-cli tool without supplying a --catalyst-pipeline argument. In such cases, the tool gets a default pipeline using the getDefaultPipeline() function, which contained an incorrect std::vector initialization resulting in an index-out-of-bounds assertion error. Furthermore, the bug was never picked up because the cli test suite was never registered in the CMake config.

Description of the Change: This change correctly initializes a vector in getDefaultPipeline() to avoid the index-out-of-bounds assert and registers the cli test suite in the CMake config. It also makes an opportunistic typo fix ("pipline" -> "pipeline")

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