[clang] Fix format specifiers fixits

This diff fixes printf "fixits" in the case when there is 
a wrapping macro and the format string needs multiple replacements. 
In the presence of a macro there is an extra logic in EditedSource.cpp
to handle multiple uses of the same macro argument 
(see the old comment inside EditedSource::canInsertInOffset)
which was mistriggerred when the argument was used only once 
but required multiple adjustments), as a result the "fixit" 
was breaking down the format string
by dropping the second format specifier, i.e. 
Log1("test 4: %s %s", getNSInteger(), getNSInteger()) 
was getting replaced with 
Log1("test 4: %ld ", (long)getNSInteger(), (long)getNSInteger()) 
(if one removed the macro and used printf directly it would work fine).
In this diff we track the location where the macro argument is used and 
(as it was before) the modifications originating from all the locations 
except the first one are rejected, but multiple changes are allowed.

Test plan: make check-all

Differential revision: https://reviews.llvm.org/D33976

llvm-svn: 305018