Add Checked Blocks/Pragmas to Olden/em3d, Olden/health, Olden/mst

[lenary]

This adds Checked blocks and pragmas to as much code in the following benchmarks as possible:

• Olden/em3d
• Olden/health
• Olden/mst

In almost all cases I've tried to keep the number of changed lines to a reasonable minimum.

Local benchmark headers have had a #pragma BOUNDS_CHECKED ON at the top, and importantly, #pragma BOUNDS_CHECKED OFF at the bottom, so that we don't have to reorder any other headers.

With logging, I've tried to keep chatting invocations on one line, rather than having the checked block start on the previous line.

There's a bug on Mac OS X where NULL is a macro that expands (via __DARWIN_NULL) to ((void*) 0) which is annoying, so I added a hack to stdlib_checked.h to get rid of the error. This seemed a reasonable approach, but I've not seen the equivalent errors on Linux yet.

This caught two unintended uses of unchecked pointers in Olden/em3d, which is good. I've fixed them in this PR.

There's still an issue with bounds interop types and calloc, but I've not seen the same error with any other functions, which is fantastic (all printf's are inside unchecked blocks as we don't yet support null-terminated strings)

[msftclas]

@lenary,
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[lenary]

With the fixes to checkedc/checkedc-clang#302, this changes all pass the static analysis, and there are no more errors with calloc.

[dtarditi]

Looks good!