[clang] [clang][AArch64] Consolidate codegen tests for SVE's LEN intrinsics (PR #226131)

[LLVM Continuous Integration via cfe-commits]

llvm-ci wrote:

LLVM Buildbot has detected a new failure on builder `clang-aarch64-sve2-vla-2stage` running on `linaro-g4-01` while building `clang` at step 19 "test-suite".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/199/builds/11053

<details>
<summary>Here is the relevant piece of the build log for the reference</summary>

```
Step 19 (test-suite) failure: test (failure)
...
size..init_array: 16 
size..interp: 27 
size..note.ABI-tag: 32 
size..plt: 352 
size..rela.dyn: 600 
size..rela.plt: 480 
size..rodata: 168 
size..text: 3896 
********************
NOEXE: test-suite :: SingleSource/UnitTests/Vectorizer/tf-ftic-runtime-checks.test (10316 of 10439)
******************** TEST 'test-suite :: SingleSource/UnitTests/Vectorizer/tf-ftic-runtime-checks.test' FAILED ********************
Executable '/home/tcwg-buildbot/worker/clang-aarch64-sve2-vla-2stage/test/sandbox/build/SingleSource/UnitTests/Vectorizer/tf-ftic-runtime-checks' is missing
********************
NOEXE: test-suite :: SingleSource/UnitTests/Vectorizer/tf-runtime-checks.test (10317 of 10439)
******************** TEST 'test-suite :: SingleSource/UnitTests/Vectorizer/tf-runtime-checks.test' FAILED ********************
Executable '/home/tcwg-buildbot/worker/clang-aarch64-sve2-vla-2stage/test/sandbox/build/SingleSource/UnitTests/Vectorizer/tf-runtime-checks' is missing
********************
PASS: test-suite :: SingleSource/UnitTests/Vectorizer/tfactivelanemask-any-of.test (10318 of 10439)
********** TEST 'test-suite :: SingleSource/UnitTests/Vectorizer/tfactivelanemask-any-of.test' RESULTS **********
compile_maxrss: 0 
compile_time: 0.0000 
exec_time: 0.0000 
hash: "a1c9b44f4054e3ae85c9beb6a1139b39" 
link_maxrss: 0 
link_time: 0.0320 
size: 48624 
size..bss: 5016 
size..comment: 153 
size..data: 24 
size..data.rel.ro: 256 
size..dynamic: 528 
size..dynstr: 717 
size..dynsym: 768 
size..eh_frame: 1984 
size..eh_frame_hdr: 556 
size..fini: 20 
size..fini_array: 8 
size..gcc_except_table: 1644 
size..gnu.hash: 28 
size..gnu.version: 64 
size..gnu.version_r: 192 
size..got: 72 
size..got.plt: 208 
size..init: 24 
size..init_array: 16 
size..interp: 27 
size..note.ABI-tag: 32 
size..plt: 400 
size..rela.dyn: 1080 

```

</details>

https://github.com/llvm/llvm-project/pull/226131