core_arch: Remove redundant LoongArch64 SIMD tests

[heiher]

Remove redundant LoongArch64 SIMD intrinsic tests from core_arch, as they are covered by intrinsic-test.

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[heiher]

Depends on #2226

[folkertdev]

For x86_64 we've mostly kept these tests, they are faster to run and deterministic. We can drop tests if really all they check is that the intrinsic is hooked up I guess.

But also the intrinsic tests do some filtering (e.g. skip anything with an argument that is a pointer), so they don't test everything.

[heiher]

Thanks! Let's keep these tests.