This fixes two issues related to Code object allocation: Code objects
need to be aligned to kCodeAlignment (= 32), and the instruction cache
needs to be flushed after deserialization.

Both bugs combined manifested as a crash at a basically arbitrary point
in the code after the Runtime::kDeserializeLazy call:

0x286bc8dc:  blx     r12     // Call to Runtime::kDeserializeLazy,
                             // generated through
                             // GenerateTailCallToReturnedCode.
0x286bc8e0:  mov     r2, r0  // This seemingly innocent register move
                             // crashes hard.

Bug: v8:6624,v8:6796
Change-Id: I88c7eaf57ac851745fb7e800c92b0f5978b33466
Reviewed-on: https://chromium-review.googlesource.com/660119Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
Commit-Queue: Jakob Gruber <jgruber@chromium.org>
Cr-Commit-Position: refs/heads/master@{#47947}