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/SBModuleSpec.cpp

@@ -82,11 +82,11 @@ void SBModuleSpec::SetTriple(const char *triple) {
 }
 
 const uint8_t *SBModuleSpec::GetUUIDBytes() {
-  return (const uint8_t *)m_opaque_ap->GetUUID().GetBytes();
+  return m_opaque_ap->GetUUID().GetBytes().data();
 }
 
 size_t SBModuleSpec::GetUUIDLength() {
-  return m_opaque_ap->GetUUID().GetByteSize();
+  return m_opaque_ap->GetUUID().GetBytes().size();
 }
 
 bool SBModuleSpec::SetUUIDBytes(const uint8_t *uuid, size_t uuid_len) {