Reland "Reland "[partition_alloc] Add alternate bucket distribution for PartitionAlloc""

This is a reland of 3fdc7489e8bcd49697bc8d4b9bf2ba66b117cfaa

This fixes a test that failed on some 32-bit platforms. The code itself
is unchanged from the previous version aside from this test.

Original change's description:
> Reland "[partition_alloc] Add alternate bucket distribution for PartitionAlloc"
>
> This is a reland of bb317f4dd5a6700756ab5a507e76538d8c35b550
>
> Original change's description:
> > [partition_alloc] Add alternate bucket distribution for PartitionAlloc
> >
> > This should not change any behaviour, but merely allow us to run a Finch
> > experiment comparing the two distribution.
> >
> > Bug: None
> > Change-Id: Ifaac5a1cbcf5d21ce44fa626f57b91a3ed4d7a69
> > Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3272015
> > Reviewed-by: Benoit Lize <[email protected]>
> > Reviewed-by: Kentaro Hara <[email protected]>
> > Commit-Queue: Thiabaud Engelbrecht <[email protected]>
> > Cr-Commit-Position: refs/heads/main@{#965816}
>
> Bug: None
> Change-Id: I111e1a0dca8049e9c8d412fd0f5ca5eb8fa9104c
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3442629
> Reviewed-by: Kentaro Hara <[email protected]>
> Reviewed-by: Benoit Lize <[email protected]>
> Commit-Queue: Thiabaud Engelbrecht <[email protected]>
> Cr-Commit-Position: refs/heads/main@{#968373}

Bug: None
Change-Id: Iad2bdafd2e352add0ba5272b09d632144f5eba59
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3459515
Reviewed-by: Kentaro Hara <[email protected]>
Reviewed-by: Benoit Lize <[email protected]>
Commit-Queue: Thiabaud Engelbrecht <[email protected]>
Cr-Commit-Position: refs/heads/main@{#971984}
diff --git a/base/allocator/partition_alloc_features.cc b/base/allocator/partition_alloc_features.cc
index a5afcc7..41fdab22 100644
--- a/base/allocator/partition_alloc_features.cc
+++ b/base/allocator/partition_alloc_features.cc
@@ -78,6 +78,12 @@
 
 #endif  // BUILDFLAG(USE_PARTITION_ALLOC_AS_MALLOC)
 
+// If enabled, switches the bucket distribution to an alternate one. The
+// alternate distribution must have buckets that are a subset of the default
+// one.
+const Feature kPartitionAllocUseAlternateDistribution{
+    "PartitionAllocUseAlternateDistribution", FEATURE_DISABLED_BY_DEFAULT};
+
 // If enabled, switches PCScan scheduling to a mutator-aware scheduler. Does not
 // affect whether PCScan is enabled itself.
 const Feature kPartitionAllocPCScanMUAwareScheduler{