[clang] [analyzer] Drop assertion enforcing that assume args are known constants (PR #151908)

[LLVM Continuous Integration via cfe-commits]

llvm-ci wrote:

LLVM Buildbot has detected a new failure on builder `llvm-clang-x86_64-sie-ubuntu-fast` running on `sie-linux-worker` while building `clang` at step 6 "test-build-unified-tree-check-all".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/144/builds/32123

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

```
Step 6 (test-build-unified-tree-check-all) failure: test (failure)
******************** TEST 'Clang :: Analysis/cxx23-assume-attribute.cpp' FAILED ********************
Exit Code: 1

Command Output (stderr):
--
/home/buildbot/buildbot-root/llvm-clang-x86_64-sie-ubuntu-fast/build/bin/clang -cc1 -internal-isystem /home/buildbot/buildbot-root/llvm-clang-x86_64-sie-ubuntu-fast/build/lib/clang/22/include -nostdsysteminc -analyze -setup-static-analyzer -std=c++23 -triple x86_64-pc-linux-gnu    -analyzer-checker=core,debug.ExprInspection -verify /home/buildbot/buildbot-root/llvm-clang-x86_64-sie-ubuntu-fast/llvm-project/clang/test/Analysis/cxx23-assume-attribute.cpp # RUN: at line 1
+ /home/buildbot/buildbot-root/llvm-clang-x86_64-sie-ubuntu-fast/build/bin/clang -cc1 -internal-isystem /home/buildbot/buildbot-root/llvm-clang-x86_64-sie-ubuntu-fast/build/lib/clang/22/include -nostdsysteminc -analyze -setup-static-analyzer -std=c++23 -triple x86_64-pc-linux-gnu -analyzer-checker=core,debug.ExprInspection -verify /home/buildbot/buildbot-root/llvm-clang-x86_64-sie-ubuntu-fast/llvm-project/clang/test/Analysis/cxx23-assume-attribute.cpp
error: 'expected-warning' diagnostics seen but not expected: 
  File /home/buildbot/buildbot-root/llvm-clang-x86_64-sie-ubuntu-fast/llvm-project/clang/test/Analysis/cxx23-assume-attribute.cpp Line 75: assumption is ignored because it contains (potential) side-effects
1 error generated.

--

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


```

</details>

https://github.com/llvm/llvm-project/pull/151908