[compiler-rt] [scudo] Add -Wconversion for tests and clean-up warnings. (PR #66147)

[Mitch Phillips via llvm-commits]

================
@@ -345,7 +345,7 @@ SCUDO_TYPED_TEST(ScudoCombinedTest, ReallocateLargeIncreasing) {
   // we preserve the data in the process.
   scudo::uptr Size = 16;
   void *P = Allocator->allocate(Size, Origin);
-  const char Marker = 0xab;
+  const char Marker = '\xab';
----------------
hctim wrote:

Maybe just use 'A' here as well, rather than the hex escape prefix?

https://github.com/llvm/llvm-project/pull/66147