Merge M45: Add support for int 2e fallback system call stub in Win10.

BUG=522201
TEST=sbox_integration_tests on Win 10 build 10525

Review URL: https://codereview.chromium.org/1291043003

Cr-Commit-Position: refs/heads/master@{#344588}
(cherry picked from commit 1453ac3a6d190b21e04d578d5cf71ce19877db47)

Review URL: https://codereview.chromium.org/1308563005.

Cr-Commit-Position: refs/branch-heads/2454@{#394}
Cr-Branched-From: 12bfc3360892ec53cd00fc239a47e5298beb063b-refs/heads/master@{#338390}
1 file changed