lldb-server tests: Propagate environment variables (pr34192)

[labath]

Summary

Without this, the launching of the test inferior may fail if it depends
on some component of the environment (most likely LD_LIBRARY_PATH). This
makes sure we propagate the environment variable to the inferior
process.

unittests/tools/lldb-server/tests/TestClient.cpp

bool TestClient::StopDebugger() {
   // Debugserver (non-conformingly?) sends a reply to the k packet instead of
   // simply closing the connection.
   PacketResult result =
       IsDebugServer() ? PacketResult::Success : PacketResult::ErrorDisconnected;
   return SendMessage("k", response, result);
 }
 
 bool TestClient::SetInferior(llvm::ArrayRef<std::string> inferior_args) {
+  StringList env;
+  Host::GetEnvironment(env);
+  for (size_t i = 0; i < env.GetSize(); ++i) {
+    if (SendEnvironmentPacket(env[i].c_str()) != 0) {
+      GTEST_LOG_(ERROR) << "failed to set environment variable `" << env[i] << "`";
+      return false;
+    }
+  }
   std::stringstream command;
   command << "A";
   for (size_t i = 0; i < inferior_args.size(); i++) {
     if (i > 0)
       command << ',';
     std::string hex_encoded = toHex(inferior_args[i]);
     command << hex_encoded.size() << ',' << i << ',' << hex_encoded;
   }