Sample profiles - Add a name table to the binary encoding.

Sample profiles - Add a name table to the binary encoding.

Binary encoded profiles used to encode all function names inline at
every reference.  This is clearly suboptimal in terms of space.  This
patch fixes this by adding a name table to the header of the file.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@250241 91177308-0d34-0410-b5e6-96231b3b80d8