[llvm-symbolizer] Add --output-style switch.
In general, llvm-symbolizer follows the output style of GNU's addr2line.
However, there are still some differences; in particular, for a requested
address, llvm-symbolizer prints line and column, while addr2line prints
only the line number.
This patch adds a new switch to select the preferred style.
Differential Revision: https://reviews.llvm.org/D60190