Test all <build attribute, value> pairs.

Add more tests to make sure the encoding/decoding of build attributes works
correctly for all permissible values of build attributes. For cases where there
are an infinite number of such values, a representative subset has been settled
for.

Change-Id: I2643c9624c211b2d56405306e16eec2d487bc5d6

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@222917 91177308-0d34-0410-b5e6-96231b3b80d8
[msan] Fix origin propagation for select of floats.

MSan does not assign origin for instrumentation temps (i.e. the ones that do
not come from the application code), but "select" instrumentation erroneously
tried to use one of those.

https://code.google.com/p/memory-sanitizer/issues/detail?id=78


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@222918 91177308-0d34-0410-b5e6-96231b3b80d8