This adjusts the test diffing to ignore the whitespace changes across
different platforms. `raw_fd_ostream` will write out `OF_Text` files
with the platform's line endings, which may differ from the source
file's.
This converts the instances of the pattern for which we have a proper
substitution in lit. This will make it easier to replace it
appropriately with Windows equivalents.
The clang::RewriteBuffer can do weird things when seeing multiple
replacements where the replacement text is one character longer or
one character shorter than the range it is replacing.
rdar://problem/32234525
