[lldb] Fix `TestDataFormatterStdList` regression

Since D66174 I see failures of TestDataFormatterStdList in about 50% of runs on
Fedora 30 x86_64 libstdc++. I have found out that LLDB internally expects these
RegularExpressions to be matched in their alphabetical order:
	^std::(__cxx11::)?list<.+>(( )?&)?$
	^std::__[[:alnum:]]+::list<.+>(( )?&)?$

But since D66174 they are sometimes matched in reverse order. In fact it was
only some luck it worked before as there is internally
std::map<lldb::RegularExpressionSP, FormatterImpl> (FormattersContainer).

Differential Revision: https://reviews.llvm.org/D66398

llvm-svn: 369655