If the stack size is > 4K, emit chkstk, which probes the stack to commit
the pages required to support the large stack.

Bug: swiftshader:25
Change-Id: Iac1850c528460f4244f6f14f851ef47ee5a737d0
Reviewed-on: https://swiftshader-review.googlesource.com/c/SwiftShader/+/41388Tested-by: Antonio Maiorano <amaiorano@google.com>
Reviewed-by: Nicolas Capens <nicolascapens@google.com>
Kokoro-Presubmit: kokoro <noreply+kokoro@google.com>