Add lldb-vscode as a dependency of lldb tests.

[jgorbe]

Summary

In the current state, 'ninja check-lldb' runs the lldb-vscode tests, but it
won't rebuild lldb-vscode if any of its sources has changed. This is very
confusing when you fix something and the tests keep failing, or vice versa.

lldb/CMakeLists.txt

if(LLDB_INCLUDE_TESTS)
   if(TARGET debugserver)
     list(APPEND LLDB_TEST_DEPS debugserver)
   endif()
 
   if(TARGET lldb-mi)
     list(APPEND LLDB_TEST_DEPS lldb-mi)
   endif()
 
+  if(TARGET lldb-vscode)
+    list(APPEND LLDB_TEST_DEPS lldb-vscode)
+  endif()
+
   if(TARGET lldb-instr)
     list(APPEND LLDB_TEST_DEPS lldb-instr)
   endif()
 
   if(NOT LLDB_BUILT_STANDALONE)
     list(APPEND LLDB_TEST_DEPS yaml2obj)
   endif()