Modernize UUID class

Instead of a separate GetBytes + GetByteSize methods I introduce a
single GetBytes method returning an ArrayRef.

This is NFC cleanup now, but it should make handling arbitrarily-sized
UUIDs cleaner, should we choose to go that way. I also took the
opportunity to add some unit tests for this class.

llvm-svn: 335244

lldb/source/API/SBModule.cpp

@@ -144,7 +144,7 @@ const uint8_t *SBModule::GetUUIDBytes() const {
   const uint8_t *uuid_bytes = NULL;
   ModuleSP module_sp(GetSP());
   if (module_sp)
-    uuid_bytes = (const uint8_t *)module_sp->GetUUID().GetBytes();
+    uuid_bytes = module_sp->GetUUID().GetBytes().data();
 
   if (log) {
     if (uuid_bytes) {