[heap] Clear current_capacity_ when uncommitting SemiSpace.

Bug: chromium:1054771
Change-Id: I58a49461723d8444fca8c2a3b0f3e75367604c76
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2562257Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Commit-Queue: Hannes Payer <hpayer@chromium.org>
Cr-Commit-Position: refs/heads/master@{#71437}

src/heap/new-spaces.cc

@@ -136,6 +136,7 @@ bool SemiSpace::Uncommit() {
     heap()->memory_allocator()->Free<MemoryAllocator::kPooledAndQueue>(chunk);
   }
   current_page_ = nullptr;
+  current_capacity_ = 0;
   AccountUncommitted(target_capacity_);
   heap()->memory_allocator()->unmapper()->FreeQueuedChunks();
   return true;