BaseTools:Fixed an issue where the order of GuidS changed in guid.xref

BaseTools:Fixed an issue where the order of GuidS changed in guid.xref

BZ:https://bugzilla.tianocore.org/show_bug.cgi?id=1749

Add content to dsc
[PcdsPatchableInModule.common]
  gEfiMdeModulePkgTokenSpaceGuid.test1|FALSE

The order of file Guid.xref will change after increment build.
The root cause is set() is used in Get all the PCDS
the order of the data may change if set() is used

This patch is going to fix that issue.

Cc: Bob Feng <bob.c.feng@intel.com>
Cc: Liming Gao <liming.gao@intel.com>
Signed-off-by: Zhiju.Fan <zhijux.fan@intel.com>
Reviewed-by: Bob Feng <bob.c.feng@intel.com>