Add color to the default thread and frame format.

Now that we correctly ignore ASCII escape sequences when colors are
disabled (r362240), I'd like to change the default frame and thread
format to include color in their output, in line with the syntax
highlighting that Raphael added a while ago.

This patch adds highlighting for the stop reason, the file, line and
column number. With colors disabled, this of course is a no-op.

Differential revision: https://reviews.llvm.org/D62743

llvm-svn: 363608