[llvm] Refactor try demangle for vfabi to use only the vector abi mangled names (PR #67430)

[via llvm-commits]

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@@ -27,15 +27,17 @@ extern "C" int LLVMFuzzerTestOneInput(const uint8_t *Data, size_t Size) {
   // present. We need to make sure we can even invoke
   // `getOrInsertFunction` because such method asserts on strings with
   // zeroes.
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JolantaJensen wrote:

I'm not sure about this test. The comment is definitely wrong now but does the test still make sense?

https://github.com/llvm/llvm-project/pull/67430