[clang] [AArch64][SME2] Add SQRSHRN, UQRSHRN, SQRSHRUN builtins for SME2, SVE2p1 (PR #75325)

[Jay Foad via cfe-commits]

jayfoad wrote:

Please remember to add a suitable `REQUIRES:` line to these new codegen tests, or put them in an `ARM` subdirectory with a suitable `lit.local.cfg`!

This new test is failing in non-ARM builds with:
```
FAIL: Clang :: CodeGen/aarch64-sve2p1-intrinsics/acle_sve2p1_qrshr.c (5567 of 76786)
******************** TEST 'Clang :: CodeGen/aarch64-sve2p1-intrinsics/acle_sve2p1_qrshr.c' FAILED ********************
Exit Code: 1

Command Output (stderr):
--
RUN: at line 2: /jenkins/workspace/llvm-llpc/llvm-npi-merge/llvm-project/build/bin/clang -cc1 -internal-isystem /jenkins/workspace/llvm-llpc/llvm-npi-merge/llvm-project/build/lib/clang/18/include -nostdsysteminc -triple aarch64-none-linux-gnu -target-feature +sve -target-feature +sme2 -S -disable-O0-optnone -Werror -Wall -emit-llvm -o - /jenkins/workspace/llvm-llpc/llvm-npi-merge/llvm-project/clang/test/CodeGen/aarch64-sve2p1-intrinsics/acle_sve2p1_qrshr.c | /jenkins/workspace/llvm-llpc/llvm-npi-merge/llvm-project/build/bin/opt -S  -passes=mem2reg,instcombine,tailcallelim | /jenkins/workspace/llvm-llpc/llvm-npi-merge/llvm-project/build/bin/FileCheck /jenkins/workspace/llvm-llpc/llvm-npi-merge/llvm-project/clang/test/CodeGen/aarch64-sve2p1-intrinsics/acle_sve2p1_qrshr.c
+ /jenkins/workspace/llvm-llpc/llvm-npi-merge/llvm-project/build/bin/clang -cc1 -internal-isystem /jenkins/workspace/llvm-llpc/llvm-npi-merge/llvm-project/build/lib/clang/18/include -nostdsysteminc -triple aarch64-none-linux-gnu -target-feature +sve -target-feature +sme2 -S -disable-O0-optnone -Werror -Wall -emit-llvm -o - /jenkins/workspace/llvm-llpc/llvm-npi-merge/llvm-project/clang/test/CodeGen/aarch64-sve2p1-intrinsics/acle_sve2p1_qrshr.c
+ /jenkins/workspace/llvm-llpc/llvm-npi-merge/llvm-project/build/bin/opt -S -passes=mem2reg,instcombine,tailcallelim
+ /jenkins/workspace/llvm-llpc/llvm-npi-merge/llvm-project/build/bin/FileCheck /jenkins/workspace/llvm-llpc/llvm-npi-merge/llvm-project/clang/test/CodeGen/aarch64-sve2p1-intrinsics/acle_sve2p1_qrshr.c
/jenkins/workspace/llvm-llpc/llvm-npi-merge/llvm-project/clang/test/CodeGen/aarch64-sve2p1-intrinsics/acle_sve2p1_qrshr.c:10:10: fatal error: 'arm_sve.h' file not found
   10 | #include <arm_sve.h>
      |          ^~~~~~~~~~~
1 error generated.
/jenkins/workspace/llvm-llpc/llvm-npi-merge/llvm-project/clang/test/CodeGen/aarch64-sve2p1-intrinsics/acle_sve2p1_qrshr.c:22:17: error: CHECK-LABEL: expected string not found in input
// CHECK-LABEL: @test_svqrshrn_s16_s32_x2(
                ^
<stdin>:1:1: note: scanning from here
; ModuleID = '<stdin>'
^
<stdin>:1:14: note: possible intended match here
; ModuleID = '<stdin>'
             ^

Input file: <stdin>
Check file: /jenkins/workspace/llvm-llpc/llvm-npi-merge/llvm-project/clang/test/CodeGen/aarch64-sve2p1-intrinsics/acle_sve2p1_qrshr.c

-dump-input=help explains the following input dump.

Input was:
<<<<<<
            1: ; ModuleID = '<stdin>' 
label:22'0     X~~~~~~~~~~~~~~~~~~~~~~ error: no match found
label:22'1                  ?          possible intended match
            2: source_filename = "<stdin>" 
label:22'0     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>>>>>>
```

https://github.com/llvm/llvm-project/pull/75325