Reverse two pthread_internal_t fields

The golang runtime currently expects to find the pthread key data after
the tls slots.

Bug: http://b/78026329
Bug: http://b/118381796
Test: run a golang-based app, bionic unit tests
Change-Id: Idc777d809b803093e1c81d9a2ce4eafcc7d61f8d
Merged-In: Idc777d809b803093e1c81d9a2ce4eafcc7d61f8d
(cherry picked from commit a2c30723)