BaseTools: Fix eval parse string issue

BaseTools: Fix eval parse string issue

eval argument start with " or ', but it is unicode string,
will encounter error:
    List = list(eval(Value)) # translate escape character
  File "<string>", line 1
    'j??=????????F??
             ^
SyntaxError: EOL while scanning string literal

Cc: Liming Gao <liming.gao@intel.com>
Cc: Yonghong Zhu <yonghong.zhu@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Yunhua Feng <yunhuax.feng@intel.com>
Reviewed-by: Yonghong Zhu <yonghong.zhu@intel.com>