[clang] [ubsan] Remove -fsanitizer=vptr from -fsanitizer=undefined (PR #121115)

[Vitaly Buka via cfe-commits]

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@@ -214,13 +214,14 @@ Available checks are:
      the wrong dynamic type, or that its lifetime has not begun or has ended.
      Incompatible with ``-fno-rtti``. Link must be performed by ``clang++``, not
      ``clang``, to make sure C++-specific parts of the runtime library and C++
-     standard libraries are present.
+     standard libraries are present. The check is not a part of the ``undefined``
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vitalybuka wrote:

Unnecessary, but probably usefull

https://github.com/llvm/llvm-project/pull/121115