[clang] [Clang][NEON] Add neon target guard to intrinsics (PR #98624)

[Maciej Gabka via cfe-commits]

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+// RUN: %clang_cc1 -triple aarch64-none-linux-gnu -target-feature +dotprod  -target-feature +fullfp16 -target-feature +fp16fml -target-feature +i8mm -target-feature +bf16 -verify -emit-llvm -o - %s
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+// This test is testing the diagnostics that Clang emits when compiling without '+neon'.
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mgabka wrote:

do we have a positive Sema tests to show that the intrinsics are available when the neon feature is present?

https://github.com/llvm/llvm-project/pull/98624