message: [XLA:Python] Actually make BFCAllocator allocate 90% up-front.
  I accidentally kept the default memory fraction at 100%, which can
  cause OOMs when preallocating.
diff: @@ -152,7 +152,7 @@ struct AllocatorConfig {
  // Only used if kind == kBFC. The maximum fraction of available memory to
  // allocate.
  - double memory_fraction = 1.0;
  + double memory_fraction = 0.9;
  // Only used if kind == kBFC. If true, the allocator will immediately allocate
  // the maximum amount allowed by `memory_fraction`. This reduces
  