[JITLink] Minor fix to avoid Windows compiler warning for static-cast

[dstuttard]

Summary

Change-Id: Id0c1d5535b53e2aebe314151c0efa585e763f3f6

[dstuttard]

Windows builds give a warning without this change

[dstuttard]

ping

[foad]

LGTM. The warning is still showing up in Windows buildbots e.g. https://lab.llvm.org/buildbot/#/builders/86/builds/12569

C:\buildbot\as-builder-3\llvm-clang-x86_64-win-fast\llvm-project\llvm\lib\ExecutionEngine\JITLink\x86_64.cpp(60): warning C4309: 'static_cast': truncation of constant value

As an alternative I think you could write just char(0xFF). Both approaches have been used in the past according to git log --grep "truncation of constant value"

llvm/lib/ExecutionEngine/JITLink/x86_64.cpp

default:
     return getGenericEdgeKindName(static_cast<Edge::Kind>(K));
   }
 }
 
 const char NullPointerContent[8] = {0x00, 0x00, 0x00, 0x00,
                                     0x00, 0x00, 0x00, 0x00};
 
 const char PointerJumpStubContent[6] = {
-    static_cast<char>(0xFF), 0x25, 0x00, 0x00, 0x00, 0x00};
+    static_cast<char>(0xFFu), 0x25, 0x00, 0x00, 0x00, 0x00};
 
 } // end namespace x86_64
 } // end namespace jitlink
 } // end namespace llvm