ART: Change main-thread thread paging scheme

Modify the code that ensures we can install a stack guard page into
the main thread.

A recent kernel change means that our previous approach of using a
free pointer does not work. It is important to actually extend the
stack properly. For portability, use a function with a large stack
frame (suggested by and adapted from hboehm).

(cherry picked from commit 6c63f863f9dbf734732ff837c1e772b3482e59ff)

Bug: 62952017
Test: m
Test: m test-art-host
Test: Device boots (x86_64 emulator)
Test: Device boots (bullhead)
Merged-In: Ic2a0c3d6d05a1ea9f655329d147b46949e1b9db3
Change-Id: Ic2a0c3d6d05a1ea9f655329d147b46949e1b9db3
(cherry picked from commit b3ab1256d1b4f335604addb373e323bf12bf1a7f)
1 file changed