PNaCl: Update llvm revision in pnacl/COMPONENT_REVISIONS
PNaCl: Update llvm revision in pnacl/COMPONENT_REVISIONS

This pulls in the following LLVM change:

a7e65db: (dschuff@chromium.org) Auto-sandboxing: add support for a few missing ARM opcodes

TBR=phosek@chromium.org
TEST= PNaCl toolchain trybots

Review URL: https://codereview.chromium.org/1643963004 .

sbc100/native_client,sbc100/native_client,sbc100/native_client,sbc100/native_client,sbc100/native_client,sbc100/native_client