Revert "Reland "[turbofan] Temporarily disable future=>concurrent_inlining""

This reverts commit 46f9d400.

Reason for revert: as planned

Original change's description:
> Reland "[turbofan] Temporarily disable future=>concurrent_inlining"
> 
> This is a reland of ce421122.
> Speculatively relanding, because the failure seems unrelated.
> 
> Original change's description:
> > [turbofan] Temporarily disable future=>concurrent_inlining
> >
> > ... in order to reset the benchmarks now that we are actually running
> > in the background.
> >
> > Bug: v8:7790
> > Change-Id: Ifa811fbcc51eccef790e6215d330f8b45c31a492
> > Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1801836
> > Reviewed-by: Georg Neis <neis@chromium.org>
> > Commit-Queue: Georg Neis <neis@chromium.org>
> > Auto-Submit: Maya Lekova <mslekova@chromium.org>
> > Cr-Commit-Position: refs/heads/master@{#63741}
> 
> Bug: v8:7790
> Change-Id: I49316516b300e6d2754043848d95ac5511fc6015
> Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1801849
> Reviewed-by: Georg Neis <neis@chromium.org>
> Commit-Queue: Georg Neis <neis@chromium.org>
> Auto-Submit: Maya Lekova <mslekova@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#63755}

TBR=neis@chromium.org,mslekova@chromium.org

# Not skipping CQ checks because original CL landed > 1 day ago.

Bug: v8:7790
Change-Id: Ic31f1bf47c0b00ec497452fd29d8c09a32e14316
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1803642Reviewed-by: Georg Neis <neis@chromium.org>
Commit-Queue: Georg Neis <neis@chromium.org>
Cr-Commit-Position: refs/heads/master@{#63779}

src/flags/flag-definitions.h

@@ -484,6 +484,7 @@ DEFINE_BOOL(block_concurrent_recompilation, false,
             "block queued jobs until released")
 DEFINE_BOOL(concurrent_inlining, false,
             "run optimizing compiler's inlining phase on a separate thread")
+DEFINE_IMPLICATION(future, concurrent_inlining)
 DEFINE_BOOL(trace_heap_broker_verbose, false,
             "trace the heap broker verbosely (all reports)")
 DEFINE_BOOL(trace_heap_broker, false,