Crash in Tehreer stack on '\n' character

[heybdj]

Given the input string "A\nB", the Tehreer stack will crash when creating the second line of the run. The fix is to pass the paragraph starting offset to SBParagraphCreateLine(...) here:

text-rendering-tests/src/fonttest/tehreerstack_line.cpp

Line 152 in f9535a1

SBLineRef line = SBParagraphCreateLine(paragraph, 0, paraLen);

The fix should look like this:

SBLineRef line = SBParagraphCreateLine(paragraph, paraStart, paraLen);