BaseTools: create and use a standard shared variable for '*'

add a variable for the string '*' and then use it instead of lots of '*'

Cc: Yonghong Zhu <yonghong.zhu@intel.com>
Cc: Liming Gao <liming.gao@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Jaben Carsey <jaben.carsey@intel.com>
Reviewed-by : Bob Feng <bob.c.feng@intel.com>

BaseTools/Source/Python/Common/Misc.py

@@ -1088,7 +1088,7 @@ class tdict:
     _ListType = type([])
     _TupleType = type(())
     _Wildcard = 'COMMON'
-    _ValidWildcardList = ['COMMON', 'DEFAULT', 'ALL', '*', 'PLATFORM']
+    _ValidWildcardList = ['COMMON', 'DEFAULT', 'ALL', TAB_STAR, 'PLATFORM']
 
     def __init__(self, _Single_=False, _Level_=2):
         self._Level_ = _Level_