Added gdb-remote tests around $qSupported.

Right now it just checks that qSupported returns at least
one recognized gdb stub feature.


git-svn-id: https://llvm.org/svn/llvm-project/lldb/trunk@210573 91177308-0d34-0410-b5e6-96231b3b80d8
Merge upstream llvm.org r210573 into dev-tfiala-native-protocol-linux-x86_64

Conflicts:
	test/tools/lldb-gdbserver/TestLldbGdbServer.py
Added qSupported support to llgs/lldb-platform.

Currently reports stub feature support for:
PacketSize=128k
QStartNoAckMode+ (i.e. supported)