BaseTools: Add a checking for Sources section in INF file

BZ: https://bugzilla.tianocore.org/show_bug.cgi?id=1804

Add a check to see if [Sources] section lists all the header type
files of a module. Performance impact should be minimal with this patch
since information is already being fetched for Makefile purposes. All
other information is already cached in memory. No extra IO time is needed.

Signed-off-by: Christian Rodriguez <christian.rodriguez@intel.com>
Cc: Bob Feng <bob.c.feng@intel.com>
Cc: Liming Gao <liming.gao@intel.com>
Cc: Yonghong Zhu <yonghong.zhu@intel.com>
Reviewed-by: Bob Feng <bob.c.feng@intel.com>