Two fixes for file variables:

- Even if a frame isn't present, we always try
  to use FindGlobalVariable to find variables.
  Instead of using frame->TrackGlobalVariable()
  to promote the VariableSP into a ValueObject,
  we now simply use ValueObjectVariable.

- When requesting the value of a variable, we
  allow returning of the "live version" of the
  variable -- that is, the variable in the
  target instead of a pointer to its freeze
  dried version in LLDB -- even if there is no
  process present.

llvm-svn: 146315