[lldb][test] enable thread_contains_name on linux

[da-viper]

On linux libdispatch set all the theads name as DispatchWorker because of the 16 byte limit of thread names.

https://github.com/swiftlang/swift-corelibs-libdispatch/blob/0bb6c10fa556722654917b4a18ba2dc39b18392a/src/queue.c#L6266-L6270

	#if HAVE_PTHREAD_SETNAME_NP 
	// pthread thread names are restricted to just 16 characters
	// including NUL. It does not make sense to pass the queue's
	// label as a name.
	pthread_setname_np(pthread_self(), "DispatchWorker");
	#endif

rust truncates the name that given

llvm::set_thread_name on linux currently uses the last 16 characters on linux as it tends to the more unique.

llvm-project/llvm/lib/Support/Unix/Threading.inc

Lines 183 to 196 in 88cb9d6

	void llvm::set_thread_name(const Twine &Name) {
	// Make sure the input is null terminated.
	SmallString<64> Storage;
	StringRef NameStr = Name.toNullTerminatedStringRef(Storage);
	// Truncate from the beginning, not the end, if the specified name is too
	// long. For one, this ensures that the resulting string is still null
	// terminated, but additionally the end of a long thread name will usually
	// be more unique than the beginning, since a common pattern is for similar
	// threads to share a common prefix.
	// Note that the name length includes the null terminator.
	if (get_max_thread_name_length() > 0)
	NameStr = NameStr.take_back(get_max_thread_name_length() - 1);
	(void)NameStr;

zig returns an error if the name is too long.