[clang] [LoongArch][Clang] Add tests for #110834 (PR #114509)

[Lu Weining via cfe-commits]

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@@ -0,0 +1,6 @@
+// REQUIRES: loongarch-registered-target
+// RUN: %clang_cc1 %s -fsyntax-only -triple loongarch64-linux -target-feature +lasx
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SixWeining wrote:

Add `not` and leave a `FIXME` or `TODO`. Then remove it in next commit.

https://github.com/llvm/llvm-project/pull/114509