[clang-apply-replacements] No longer deduplucates replacements from the same TU

Summary:
clang-apply-replacements currently deduplicates all diagnostic replacements. However if you get a duplicated replacement from one TU then its expected that it should not be deduplicated. This goes some way to solving [[ https://bugs.llvm.org/show_bug.cgi?id=45150 | export-fixes to yaml adds extra newlines and breaks offsets. ]]

Take this example yaml.
```
---
MainSourceFile:  '/home/nathan/test/test.cpp'
Diagnostics:
  - DiagnosticName:  readability-braces-around-statements
    DiagnosticMessage:
      Message:         statement should be inside braces
      FilePath:        '/home/nathan/test/test.cpp'
      FileOffset:      14
      Replacements:
        - FilePath:        '/home/nathan/test/test.cpp'
          Offset:          14
          Length:          0
          ReplacementText: ' {'
        - FilePath:        '/home/nathan/test/test.cpp'
          Offset:          28
          Length:          0
          R...