[llvm] [NFC][TableGen] Manually format `StringSwitch` in X86RecognizableInstr.cpp (PR #141615)

[LLVM Continuous Integration via llvm-commits]

llvm-ci wrote:

LLVM Buildbot has detected a new failure on builder `lldb-aarch64-ubuntu` running on `linaro-lldb-aarch64-ubuntu` while building `llvm` at step 6 "test".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/59/builds/18881

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

```
Step 6 (test) failure: build (failure)
...
PASS: lldb-unit :: ValueObject/./LLDBValueObjectTests/8/12 (2238 of 2248)
PASS: lldb-unit :: ValueObject/./LLDBValueObjectTests/7/12 (2239 of 2248)
PASS: lldb-unit :: ValueObject/./LLDBValueObjectTests/9/12 (2240 of 2248)
PASS: lldb-unit :: tools/lldb-server/tests/./LLDBServerTests/0/2 (2241 of 2248)
PASS: lldb-unit :: tools/lldb-server/tests/./LLDBServerTests/1/2 (2242 of 2248)
PASS: lldb-unit :: Utility/./UtilityTests/4/9 (2243 of 2248)
PASS: lldb-unit :: Host/./HostTests/10/13 (2244 of 2248)
PASS: lldb-unit :: Target/./TargetTests/11/14 (2245 of 2248)
PASS: lldb-unit :: Host/./HostTests/2/13 (2246 of 2248)
PASS: lldb-unit :: Process/gdb-remote/./ProcessGdbRemoteTests/8/9 (2247 of 2248)
command timed out: 2400 seconds without output running [b'ninja', b'check-lldb'], attempting to kill
process killed by signal 9
program finished with exit code -1
elapsedTime=2701.221837

```

</details>

https://github.com/llvm/llvm-project/pull/141615