[sandbox] Increase data size limit from 4GB to 16GB

The 4GB limit is causing real-world problems, especially for big
WebAssembly workloads.
After ref-counting is checking for overflows
(https://crrev.com/c/1622483), there is no reason to keep the limit
that low. This CL increases it to 16GB.

R=palmer@chromium.org

Bug: 912764
Change-Id: I13ab10640a578eb6835a94128ff40c2e0a6a2e49
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1786446
Commit-Queue: Clemens Hammacher <clemensh@chromium.org>
Reviewed-by: Chris Palmer <palmer@chromium.org>
Cr-Commit-Position: refs/heads/master@{#694675}

sandbox/constants.h

@@ -15,11 +15,11 @@ namespace sandbox {
 // JOBOBJECT_EXTENDED_LIMIT_INFORMATION.JobMemoryLimit on Windows.
 //
 #if defined(ARCH_CPU_64_BITS)
-const size_t kDataSizeLimit = 1ULL << 32;
+constexpr size_t kDataSizeLimit = size_t{1} << 34;  // 16 GB
 #else
 // Limit the data memory to a size that prevents allocations that can't be
 // indexed by an int.
-const size_t kDataSizeLimit =
+constexpr size_t kDataSizeLimit =
     static_cast<size_t>(std::numeric_limits<int>::max());
 #endif