[harfbuzz] Fix shaping across text runs
[harfbuzz] Fix shaping across text runs

The 3rd parameter to hb_buffer_add_utf() should be the length of the
whole text not the current run, so that HarfBuzz can take the context
into account when shaping.

Change-Id: I9e4e928d40078c3e3667cfdb6d8f24bf6e58263d

JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core,JurassicWordExcel/core