[clang] [Sema] Remove an unnecessary cast (NFC) (PR #147203)

[LLVM Continuous Integration via cfe-commits]

llvm-ci wrote:

LLVM Buildbot has detected a new failure on builder `lldb-x86_64-win` running on `as-builder-10` while building `clang` at step 8 "test-check-lldb-unit".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/211/builds/284

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

```
Step 8 (test-check-lldb-unit) failure: Test just built components: check-lldb-unit completed (failure)
******************** TEST 'lldb-unit :: Host/./HostTests.exe/31/87' FAILED ********************
Script(shard):
--
GTEST_OUTPUT=json:C:\buildbot\as-builder-10\lldb-x86-64\build\tools\lldb\unittests\Host\.\HostTests.exe-lldb-unit-14604-31-87.json GTEST_SHUFFLE=0 GTEST_TOTAL_SHARDS=87 GTEST_SHARD_INDEX=31 C:\buildbot\as-builder-10\lldb-x86-64\build\tools\lldb\unittests\Host\.\HostTests.exe
--

Script:
--
C:\buildbot\as-builder-10\lldb-x86-64\build\tools\lldb\unittests\Host\.\HostTests.exe --gtest_filter=MainLoopTest.NoSpuriousPipeReads
--
C:\buildbot\as-builder-10\lldb-x86-64\llvm-project\lldb\unittests\Host\MainLoopTest.cpp(141): error: Expected equality of these values:
  1u
    Which is: 1
  callback_count
    Which is: 2


C:\buildbot\as-builder-10\lldb-x86-64\llvm-project\lldb\unittests\Host\MainLoopTest.cpp:141
Expected equality of these values:
  1u
    Which is: 1
  callback_count
    Which is: 2



********************


```

</details>

https://github.com/llvm/llvm-project/pull/147203