UnitTestFrameworkPkg: Change OPTIONAL keyword usage style

REF: https://bugzilla.tianocore.org/show_bug.cgi?id=3760

Update all use of ', OPTIONAL' to ' OPTIONAL,' for function params.

Cc: Andrew Fish <afish@apple.com>
Cc: Leif Lindholm <leif@nuviainc.com>
Cc: Michael Kubacki <michael.kubacki@microsoft.com>
Signed-off-by: Michael D Kinney <michael.d.kinney@intel.com>
Reviewed-by: Bret Barkelew <bret.barkelew@microsoft.com>

UnitTestFrameworkPkg/Library/UnitTestLib/Log.c

@@ -109,7 +109,7 @@ VOID
 EFIAPI
 UnitTestLogInit (
   IN OUT UNIT_TEST  *Test,
-  IN     UINT8      *Buffer,     OPTIONAL
+  IN     UINT8      *Buffer      OPTIONAL,
   IN     UINTN      BufferSize   OPTIONAL
   )
 {

UnitTestFrameworkPkg/Library/UnitTestLib/UnitTestLib.c

@@ -604,7 +604,7 @@ STATIC
 UNIT_TEST_SAVE_HEADER*
 SerializeState (
   IN UNIT_TEST_FRAMEWORK_HANDLE  FrameworkHandle,
-  IN UNIT_TEST_CONTEXT           ContextToSave,      OPTIONAL
+  IN UNIT_TEST_CONTEXT           ContextToSave       OPTIONAL,
   IN UINTN                       ContextToSaveSize
   )
 {