MdeModulePkg/PeiPerformance:Updated to track FPDT record in PEI phase

MdeModulePkg/PeiPerformance:Updated to track FPDT record in PEI phase

V3:Handle the case when string is empty in String Record.

Updated to convert Pref entry to FPDT record in PEI phase and then
report the records to DxeCorePerfLib through GUID hob.

Cc: Liming Gao <liming.gao@intel.com>
Cc: Star Zeng <star.zeng@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Dandan Bi <dandan.bi@intel.com>
Reviewed-by: Liming Gao <liming.gao@intel.com>