MdePkg/BasePrintLib: Refine the SPrint functions

MdePkg/BasePrintLib: Refine the SPrint functions

For the following 12 APIs in MdePkg/BasePrintLib:
UnicodeVSPrint
UnicodeBSPrint
UnicodeSPrint
UnicodeVSPrintAsciiFormat
UnicodeBSPrintAsciiFormat
UnicodeSPrintAsciiFormat
AsciiVSPrint
AsciiBSPrint
AsciiSPrint
AsciiVSPrintUnicodeFormat
AsciiBSPrintUnicodeFormat
AsciiSPrintUnicodeFormat

They will ASSERT when:
1) The input parameter 'StartOfBuffer' is NULL if 'BufferSize' indicates
at least 1 Ascii/Unicode character can be held.
2) The input parameter 'FormatString' is NULL if 'BufferSize' indicates at
least 1 Ascii/Unicode character can be held.
3) The input parameter 'FormatString' contains more than
PcdMaximum[Ascii|Unicode]StringLength Ascii/Unicode characters.
4) The produced string contains more than
PcdMaximum[Ascii|Unicode]StringLength Ascii/Unicode characters.

This commits removes the ASSERT case 4) and add the following new ASSERT
case:
4) The input parameter 'BufferSize' is greater than
(PcdMaximumAsciiStringLength * sizeof (CHAR8)) for Ascii format string or
(PcdMaximumUnicodeStringLength * sizeof (CHAR16) + 1) for Unicode format
string.

And for those ASSERT cases, 0 will be returned by those 12 APIs.

For the following 2 APIs in MdePkg/BasePrintLib:
SPrintLength
SPrintLengthAsciiFormat

They will ASSERT when:
1) The input parameter 'FormatString' is NULL.
2) The input parameter 'FormatString' contains more than
PcdMaximum[Ascii|Unicode]StringLength Ascii/Unicode characters.

And for those ASSERT cases, 0 will be returned by those 2 APIs.

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Hao Wu <hao.a.wu@intel.com>
Reviewed-by: Liming Gao <liming.gao@intel.com>