Summary:
Right now we use valgrind built with gcc-5-glibc-2.23 which keep generating this error everywhere
```
==3224756== Conditional jump or move depends on uninitialised value(s)
==3224756== at 0x401AD68: index (in /usr/local/fbcode/gcc-4.9-glibc-2.20/lib/ld-2.20.so)
==3224756== by 0x4008933: _dl_map_object (in /usr/local/fbcode/gcc-4.9-glibc-2.20/lib/ld-2.20.so)
==3224756== by 0x4000ECC: map_doit (in /usr/local/fbcode/gcc-4.9-glibc-2.20/lib/ld-2.20.so)
==3224756== by 0x40101C7: _dl_catch_error (in /usr/local/fbcode/gcc-4.9-glibc-2.20/lib/ld-2.20.so)
==3224756== by 0x4000B34: do_preload (in /usr/local/fbcode/gcc-4.9-glibc-2.20/lib/ld-2.20.so)
==3224756== by 0x400458C: dl_main (in /usr/local/fbcode/gcc-4.9-glibc-2.20/lib/ld-2.20.so)
==3224756== by 0x40185DB: _dl_sysdep_start (in /usr/local/fbcode/gcc-4.9-glibc-2.20/lib/ld-2.20.so)
==3224756== by 0x4004F39: _dl_start (in /usr/local/fbcode/gcc-4.9-glibc-2.20/lib/ld-2.20.so)
==3224756== by 0x4000CE7: ??? (in /usr/local/fbcode/gcc-4.9-glibc-2.20/lib/ld-2.20.so)
==3224756== Uninitialised value was created by a stack allocation
==3224756== at 0x4004519: dl_main (in /usr/local/fbcode/gcc-4.9-glibc-2.20/lib/ld-2.20.so)
==3224756==
```
Test Plan: DISABLE_JEMALLOC=1 make valgrind_check -j64
Reviewers: andrewkr, yiwu, sdong
Reviewed By: sdong
Subscribers: andrewkr, dhruba
Differential Revision: https://reviews.facebook.net/D59343
edc764e91b