sanitizer_common: don't write into .rodata

setlocale interceptor imitates a write into result,
which may be located in .rodata section.
This is the only interceptor that tries to do this and
I think the intention was to initialize the range for msan.
So do that instead. Writing into .rodata shouldn't happen
(without crashing later on the actual write) and this
traps on my local tsan experiments.

Reviewed By: vitalybuka

Differential Revision: https://reviews.llvm.org/D102161