This reverts commit 4bca9dc7.

Reason for revert: Breaks mips builder:
https://build.chromium.org/p/client.v8.ports/builders/V8%20Mips%20-%20builder/builds/8600

Original change's description:
> [compiler-dispatcher] Use an integer job id.
> 
> It enables jobs without a SharedFunctionInfo.
> 
> BUG=v8:6093
> 
> Change-Id: Icc5f01512c270a55349087d418b6be82ad5c6cb4
> Reviewed-on: https://chromium-review.googlesource.com/467148
> Commit-Queue: Wiktor Garbacz <wiktorg@google.com>
> Reviewed-by: Ross McIlroy <rmcilroy@chromium.org>
> Reviewed-by: Jochen Eisinger <jochen@chromium.org>
> Reviewed-by: Marja Hölttä <marja@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#44402}

TBR=rmcilroy@chromium.org,marja@chromium.org,jochen@chromium.org,rmcilroy@google.com,wiktorg@google.com
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=v8:6093

Change-Id: Ie8d26f4e2d42f67a1cfa91269e80e407ed3f0799
Reviewed-on: https://chromium-review.googlesource.com/468887Reviewed-by: Michael Achenbach <machenbach@chromium.org>
Commit-Queue: Michael Achenbach <machenbach@chromium.org>
Cr-Commit-Position: refs/heads/master@{#44404}