[llvm] [ThinLTO] Do not duplicate import a function that is actually defined in the current module (PR #110064)

[LLVM Continuous Integration via llvm-commits]

llvm-ci wrote:

LLVM Buildbot has detected a new failure on builder `ml-opt-rel-x86-64` running on `ml-opt-rel-x86-64-b1` while building `llvm` at step 6 "test-build-unified-tree-check-all".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/185/builds/6684

<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 'LLVM :: ThinLTO/X86/ditemplatevalueparameter-remap.ll' FAILED ********************
Exit Code: 127

Command Output (stderr):
--
RUN: at line 36: /b/ml-opt-rel-x86-64-b1/build/bin/opt -module-summary -o /b/ml-opt-rel-x86-64-b1/build/test/ThinLTO/X86/Output/ditemplatevalueparameter-remap.ll.tmp1.bc /b/ml-opt-rel-x86-64-b1/llvm-project/llvm/test/ThinLTO/X86/ditemplatevalueparameter-remap.ll
+ /b/ml-opt-rel-x86-64-b1/build/bin/opt -module-summary -o /b/ml-opt-rel-x86-64-b1/build/test/ThinLTO/X86/Output/ditemplatevalueparameter-remap.ll.tmp1.bc /b/ml-opt-rel-x86-64-b1/llvm-project/llvm/test/ThinLTO/X86/ditemplatevalueparameter-remap.ll
RUN: at line 37: /b/ml-opt-rel-x86-64-b1/build/bin/opt -module-summary -o /b/ml-opt-rel-x86-64-b1/build/test/ThinLTO/X86/Output/ditemplatevalueparameter-remap.ll.tmp2.bc /b/ml-opt-rel-x86-64-b1/llvm-project/llvm/test/ThinLTO/X86/Inputs/ditemplatevalueparameter-remap.ll
+ /b/ml-opt-rel-x86-64-b1/build/bin/opt -module-summary -o /b/ml-opt-rel-x86-64-b1/build/test/ThinLTO/X86/Output/ditemplatevalueparameter-remap.ll.tmp2.bc /b/ml-opt-rel-x86-64-b1/llvm-project/llvm/test/ThinLTO/X86/Inputs/ditemplatevalueparameter-remap.ll
RUN: at line 38: ld.lld --plugin-opt=thinlto-index-only -shared /b/ml-opt-rel-x86-64-b1/build/test/ThinLTO/X86/Output/ditemplatevalueparameter-remap.ll.tmp1.bc /b/ml-opt-rel-x86-64-b1/build/test/ThinLTO/X86/Output/ditemplatevalueparameter-remap.ll.tmp2.bc
+ ld.lld --plugin-opt=thinlto-index-only -shared /b/ml-opt-rel-x86-64-b1/build/test/ThinLTO/X86/Output/ditemplatevalueparameter-remap.ll.tmp1.bc /b/ml-opt-rel-x86-64-b1/build/test/ThinLTO/X86/Output/ditemplatevalueparameter-remap.ll.tmp2.bc
/b/ml-opt-rel-x86-64-b1/build/test/ThinLTO/X86/Output/ditemplatevalueparameter-remap.ll.script: line 3: ld.lld: command not found

--

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


```

</details>

https://github.com/llvm/llvm-project/pull/110064