Fix bug introduced in r196517.

Not only does it trigger -Wparentheses, I think the assert actually
relies on incorrect operator precedence.

Also, the grammar as questionable, but I might not know enough about the
problem at hand.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@196567 91177308-0d34-0410-b5e6-96231b3b80d8
[asan] rewrite asan's stack frame layout

Summary:
Rewrite asan's stack frame layout.
First, most of the stack layout logic is moved into a separte file
to make it more testable and (potentially) useful for other projects.
Second, make the frames more compact by using adaptive redzones
(smaller for small objects, larger for large objects).
Third, try to minimized gaps due to large alignments (this is hypothetical since
today we don't see many stack vars aligned by more than 32).

The frames indeed become more compact, but I'll still need to run more benchmarks
before committing, but I am sking for review now to get early feedback.

This change will be accompanied by a trivial change in compiler-rt tests
to match the new frame sizes.

Reviewers: samsonov, dvyukov

Reviewed By: samsonov

CC: llvm-commits

Differential Revision: http://llvm-reviews.chandlerc.com/D2324

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@196568 91177308-0d34-0410-b5e6-96231b3b80d8