Revert "Reland "[NFC][compiler-rt][asan] Unify asan and lsan allocator settings""

This reverts commit b37d84aa.

This broke aarch64 asan builders for fuchsia. I accidentally changed the allocator
settings for fuchsia on aarch64 because the new asan allocator settings use:

```
// AArch64/SANITIZER_CAN_USE_ALLOCATOR64 is only for 42-bit VMA
// so no need to different values for different VMA.
const uptr kAllocatorSpace =  0x10000000000ULL;
const uptr kAllocatorSize  =  0x10000000000ULL;  // 3T.
typedef DefaultSizeClassMap SizeClassMap;
```

rather than reaching the final `#else` which would use fuchsia's lsan config.