[asan] Fix an overflow with an Allocator constant

[wang0109]

Summary

In asan on Windows 64-bit, this is one of the broken things
that makes allocation fail. "UL" is 32-bit and shift by 40 will make
the value overflow and become 0.

[etienneb]

lgtm

landing...

compiler-rt/trunk/lib/asan/asan_allocator.cc

void AllocatorOptions::CopyTo(Flags *f, CommonFlags *cf) {
   f->redzone = min_redzone;
   f->max_redzone = max_redzone;
   cf->allocator_may_return_null = may_return_null;
   f->alloc_dealloc_mismatch = alloc_dealloc_mismatch;
 }
 
 struct Allocator {
   static const uptr kMaxAllowedMallocSize =
-      FIRST_32_SECOND_64(3UL << 30, 1UL << 40);
+      FIRST_32_SECOND_64(3UL << 30, 1ULL << 40);
   static const uptr kMaxThreadLocalQuarantine =
       FIRST_32_SECOND_64(1 << 18, 1 << 20);
 
   AsanAllocator allocator;
   AsanQuarantine quarantine;
   StaticSpinMutex fallback_mutex;
   AllocatorCache fallback_allocator_cache;
   QuarantineCache fallback_quarantine_cache;