Use -fPIC instead of -fPIE for ThreadSanitizer v2

Use -fPIC instead of -fPIE for ThreadSanitizer v2

BUG=171402, 128314
TBR=thakis
Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=178276

[Alexander Potapenko, 2013-01-23 10:39:18]

TBR

[Nico, 2013-01-23 20:39:37]

Every CL description should describe why a change is done (effects, things that
are currently wrong, etc). This CL description doesn't.

I can kind of guess what it's for by reading one of the two linked bugs, but the
bug doesn't really explain a reasoning either, it's more "stuff is broken with
this flag but not with this other flag, so let's change flags".

[Alexander Potapenko, 2013-01-24 08:57:30]

Sorry about that. I used to think that a link to crbug is more important, since
it has all the relevant information. I'll be more accurate in my future commits.

For the record (if anyone is going to read this issue trying to understand why
the change has been made), the problem here is that every file in Chrome has
been compiled with -fPIE, including those ending up linked into a .so. Because
-fPIE is only applicable to executable binaries, and the targets are built only
once (i.e. there're no versions of modules for executables and shared objects),
we had to replace -fPIE with -fPIC.