refine the implementation of HiiStringToImage:

refine the implementation of HiiStringToImage:
1. Remove the limitation of MAX_STRING_LENGTH and according to actual string length to store glyph info
2. fix a issue when print multi-lines, the next line will overlaps the above line. The original implementation doesn't recalculate the start point of X/Y axis.
3. refine the flow to avoid the meaningless recursive call.
4. modify the usage of "Index" to force them 1/1 mapping between glyphbuf and string. So the RowInfoArray and ColumnInfoArray can reflect the actual situation.

git-svn-id: https://edk2.svn.sourceforge.net/svnroot/edk2/trunk/edk2@8371 6f19259b-4bc3-4df7-8a09-765794883524