BaseTools: Explicitly close files after readlines

Rework some file open().readlines to open, readlines, close.
This prevents excessive file handles being open at the same time,
which may be a problem with alternative python environments.

Cc: Liming Gao <liming.gao@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Michael Johnson <michael.johnson@intel.com>
Reviewed-by: Bob Feng <bob.c.feng@intel.com>

BaseTools/Source/Python/AutoGen/InfSectionParser.py

@@ -34,7 +34,8 @@ class InfSectionParser():
         SectionData = []
 
         try:
-            FileLinesList = open(self._FilePath, "r").readlines()
+            with open(self._FilePath, "r") as File:
+                FileLinesList = File.readlines()
         except BaseException:
             EdkLogger.error("build", AUTOGEN_ERROR, 'File %s is opened failed.' % self._FilePath)