BaseTools: Add new RegExp for future use

Add a precompiled RegExp for 4 hex chars.
v2: fixed incorrect numbers 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: Yonghong Zhu <yonghong.zhu@intel.com>

BaseTools/Source/Python/Common/GlobalData.py

@@ -59,6 +59,8 @@ _GuidPattern = r"{Hex}{{8}}-{Hex}{{4}}-{Hex}{{4}}-{Hex}{{4}}-{Hex}{{12}}".format
 gGuidPattern = re.compile(r'{}'.format(_GuidPattern))
 gGuidPatternEnd = re.compile(r'{}$'.format(_GuidPattern))
 
+g4HexChar = re.compile(r'{}{{4}}'.format(_HexChar))
+
 #
 # A global variable for whether current build in AutoGen phase or not.
 #