[clang] [clang][ARM] Fix warning for using VFP from interrupts. (PR #91870)

[Chris Copeland via cfe-commits]

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@@ -448,6 +448,11 @@ Modified Compiler Flags
   evaluating to ``true`` and an empty body such as ``while(1);``)
   are considered infinite, even when the ``-ffinite-loop`` flag is set.
 
+- Removed "arm interrupt calling convention" warning that was included in
+  ``-Wextra`` without its own flag.
+
+- Added ``-Warm-interrupt-vfp-clobber``, with its own warning group.
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chrisnc wrote:

Moved these around, and split up the content that was previously in the `Improvements to Clang's diagnostics` section.

https://github.com/llvm/llvm-project/pull/91870