[clang] [WebKit checkers] Recognize adoptRef as a safe function (PR #119846)

[LLVM Continuous Integration via cfe-commits]

llvm-ci wrote:

LLVM Buildbot has detected a new failure on builder `premerge-monolithic-linux` running on `premerge-linux-1` while building `clang` at step 7 "test-build-unified-tree-check-all".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/153/builds/18106

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

```
Step 7 (test-build-unified-tree-check-all) failure: test (failure)
******************** TEST 'Clang :: Analysis/Checkers/WebKit/local-vars-counted-const-member.cpp' FAILED ********************
Exit Code: 1

Command Output (stderr):
--
RUN: at line 1: /build/buildbot/premerge-monolithic-linux/build/bin/clang -cc1 -internal-isystem /build/buildbot/premerge-monolithic-linux/build/lib/clang/20/include -nostdsysteminc -analyze -analyzer-constraints=range -setup-static-analyzer -analyzer-checker=alpha.webkit.UncountedLocalVarsChecker -verify /build/buildbot/premerge-monolithic-linux/llvm-project/clang/test/Analysis/Checkers/WebKit/local-vars-counted-const-member.cpp
+ /build/buildbot/premerge-monolithic-linux/build/bin/clang -cc1 -internal-isystem /build/buildbot/premerge-monolithic-linux/build/lib/clang/20/include -nostdsysteminc -analyze -analyzer-constraints=range -setup-static-analyzer -analyzer-checker=alpha.webkit.UncountedLocalVarsChecker -verify /build/buildbot/premerge-monolithic-linux/llvm-project/clang/test/Analysis/Checkers/WebKit/local-vars-counted-const-member.cpp
error: 'expected-error' diagnostics seen but not expected: 
  File /build/buildbot/premerge-monolithic-linux/llvm-project/clang/test/Analysis/Checkers/WebKit/local-vars-counted-const-member.cpp Line 17: object of type 'RefPtr<RefCountable>' cannot be assigned because its copy assignment operator is implicitly deleted
  File /build/buildbot/premerge-monolithic-linux/llvm-project/clang/test/Analysis/Checkers/WebKit/local-vars-counted-const-member.cpp Line 23: object of type 'RefPtr<RefCountable>' cannot be assigned because its copy assignment operator is implicitly deleted
  File /build/buildbot/premerge-monolithic-linux/llvm-project/clang/test/Analysis/Checkers/WebKit/local-vars-counted-const-member.cpp Line 33: object of type 'RefPtr<RefCountable>' cannot be assigned because its copy assignment operator is implicitly deleted
error: 'expected-warning' diagnostics expected but not seen: 
  File /build/buildbot/premerge-monolithic-linux/llvm-project/clang/test/Analysis/Checkers/WebKit/local-vars-counted-const-member.cpp Line 24 (directive at /build/buildbot/premerge-monolithic-linux/llvm-project/clang/test/Analysis/Checkers/WebKit/local-vars-counted-const-member.cpp:25): Local variable 'next' is uncounted and unsafe [alpha.webkit.UncountedLocalVarsChecker]
  File /build/buildbot/premerge-monolithic-linux/llvm-project/clang/test/Analysis/Checkers/WebKit/local-vars-counted-const-member.cpp Line 50 (directive at /build/buildbot/premerge-monolithic-linux/llvm-project/clang/test/Analysis/Checkers/WebKit/local-vars-counted-const-member.cpp:51): Local variable 'obj2' is uncounted and unsafe [alpha.webkit.UncountedLocalVarsChecker]
  File /build/buildbot/premerge-monolithic-linux/llvm-project/clang/test/Analysis/Checkers/WebKit/local-vars-counted-const-member.cpp Line 55 (directive at /build/buildbot/premerge-monolithic-linux/llvm-project/clang/test/Analysis/Checkers/WebKit/local-vars-counted-const-member.cpp:56): Local variable 'obj4' is uncounted and unsafe [alpha.webkit.UncountedLocalVarsChecker]
  File /build/buildbot/premerge-monolithic-linux/llvm-project/clang/test/Analysis/Checkers/WebKit/local-vars-counted-const-member.cpp Line 78 (directive at /build/buildbot/premerge-monolithic-linux/llvm-project/clang/test/Analysis/Checkers/WebKit/local-vars-counted-const-member.cpp:79): Local variable 'obj2' is uncounted and unsafe [alpha.webkit.UncountedLocalVarsChecker]
  File /build/buildbot/premerge-monolithic-linux/llvm-project/clang/test/Analysis/Checkers/WebKit/local-vars-counted-const-member.cpp Line 100 (directive at /build/buildbot/premerge-monolithic-linux/llvm-project/clang/test/Analysis/Checkers/WebKit/local-vars-counted-const-member.cpp:101): Local variable 'obj2' is uncounted and unsafe [alpha.webkit.UncountedLocalVarsChecker]
error: 'expected-note' diagnostics seen but not expected: 
  File /build/buildbot/premerge-monolithic-linux/llvm-project/clang/test/Analysis/Checkers/WebKit/mock-types.h Line 128: copy assignment operator is implicitly deleted because 'RefPtr<RefCountable>' has a user-declared move constructor
  File /build/buildbot/premerge-monolithic-linux/llvm-project/clang/test/Analysis/Checkers/WebKit/mock-types.h Line 128: copy assignment operator is implicitly deleted because 'RefPtr<RefCountable>' has a user-declared move constructor
  File /build/buildbot/premerge-monolithic-linux/llvm-project/clang/test/Analysis/Checkers/WebKit/mock-types.h Line 128: copy assignment operator is implicitly deleted because 'RefPtr<RefCountable>' has a user-declared move constructor
11 errors generated.

--

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


```

</details>

https://github.com/llvm/llvm-project/pull/119846