[tsan] Fix build for FreeBSD and NetBSD after 0784b1ee (#79019)

In 0784b1ee some code for re-execution was moved to
`ReExecIfNeeded()`, but also extended with a few Linux-only features.
This leads to compile errors on FreeBSD, or other non-Linux platforms:

compiler-rt/lib/tsan/rtl/tsan_platform_linux.cpp:247:25: error: use of
undeclared identifier 'personality'
      247 |   int old_personality = personality(0xffffffff);
          |                         ^
compiler-rt/lib/tsan/rtl/tsan_platform_linux.cpp:249:54: error: use of
undeclared identifier 'ADDR_NO_RANDOMIZE'
249 | (old_personality != -1) && ((old_personality & ADDR_NO_RANDOMIZE)
== 0);
          |                                                      ^
compiler-rt/lib/tsan/rtl/tsan_platform_linux.cpp:281:46: error: use of
undeclared identifier 'ADDR_NO_RANDOMIZE'
281 | CHECK_NE(personality(old_personality | ADDR_NO_RANDOMIZE), -1);
          |                                              ^

Surround the affected part with a `#if SANITIZER_LINUX` block for now.