[sanitizer] Undef _TIME_BITS along with _FILE_OFFSET_BITS on Linux

On 32-bit glibc>=2.34 systems using 64bit time_t build fails because
_FILE_OFFSET_BITS is undefined here but _TIME_BITS is still set to 64

Fixes

```
/usr/include/features-time64.h:26:5: error: "_TIME_BITS=64 is allowed
 only with _FILE_OFFSET_BITS=64"
| #   error "_TIME_BITS=64 is allowed only with _FILE_OFFSET_BITS=64"
|     ^
| 1 error generated.
```

Reviewed By: thesamesam, MaskRay

Differential Revision: https://reviews.llvm.org/D140812

compiler-rt/lib/sanitizer_common/sanitizer_platform_limits_posix.cpp

@@ -18,6 +18,7 @@
 // depends on _FILE_OFFSET_BITS setting.
 // To get this "true" dirent definition, we undefine _FILE_OFFSET_BITS below.
 #undef _FILE_OFFSET_BITS
+#undef _TIME_BITS
 #endif
 
 // Must go after undef _FILE_OFFSET_BITS.