Remove usages of TimeValue from gdb-remote process plugin

Summary:
Most of the changes are very straight-forward, the only tricky part was the
"packet speed-test" function, which is very time-heavy. As the function was
completely untested, I added a quick unit smoke test for it.

Reviewers: clayborg, zturner

Subscribers: lldb-commits

Differential Revision: https://reviews.llvm.org/D25391

llvm-svn: 285602
diff --git a/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationClient.h b/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationClient.h
index cfdcc88..9e89544 100644
--- a/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationClient.h
+++ b/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationClient.h
@@ -244,7 +244,7 @@
 
   const ArchSpec &GetHostArchitecture();
 
-  uint32_t GetHostDefaultPacketTimeout();
+  std::chrono::seconds GetHostDefaultPacketTimeout();
 
   const ArchSpec &GetProcessArchitecture();
 
@@ -556,7 +556,7 @@
                                  // qGDBServerVersion is not supported
   uint32_t m_gdb_server_version; // from reply to qGDBServerVersion, zero if
                                  // qGDBServerVersion is not supported
-  uint32_t m_default_packet_timeout;
+  std::chrono::seconds m_default_packet_timeout;
   uint64_t m_max_packet_size;        // as returned by qSupported
   std::string m_qSupported_response; // the complete response to qSupported