If the value returned by `malloc`, `calloc` or `realloc` is not checked
for null pointer, this change replaces them for `safe_malloc`,
`safe_calloc` or `safe_realloc`, which are defined in the namespace `llvm`.
These function report fatal error on out of memory.
In the plain C files, assertion statements are added to ensure that memory
is successfully allocated.
The aim of this change is to get better diagnostics of OOM on Windows.
Differential Revision: https://reviews.llvm.org/D43017
llvm-svn: 325661
52525730a1