[SYCL] Fix memory leak. (#17632)

According to
https://github.com/llvm/llvm-project/blob/main/llvm/unittests/Demangle/OutputBufferTest.cpp,
`OutputBuffer` has to be manually freed.

Author: maarquitos14

llvm/lib/SYCLLowerIR/ESIMD/ESIMDVerifier.cpp

@@ -89,6 +89,19 @@ static const char *LegalSYCLFunctionsInStatelessMode[] = {
 
 namespace {
 
+class BuffDeleter {
+public:
+  BuffDeleter(char *Buffer) : Buff(Buffer) {};
+  ~BuffDeleter() { std::free(Buff); };
+
+  BuffDeleter() = delete;
+  BuffDeleter(const BuffDeleter &) = delete;
+  BuffDeleter(BuffDeleter &&) = delete;
+
+private:
+  char *Buff;
+};
+
 class ESIMDVerifierImpl {
   const Module &M;
   bool MayNeedForceStatelessMemModeAPI;
@@ -149,6 +162,7 @@ class ESIMDVerifierImpl {
             continue;
 
           id::OutputBuffer NameBuf;
+          BuffDeleter NameBufDeleter(NameBuf.getBuffer());
           NameNode->print(NameBuf);
           StringRef Name(NameBuf.getBuffer(), NameBuf.getCurrentPosition());