[Stackmaps] Update the stackmap format to use 64-bit relocations for the...

[Stackmaps] Update the stackmap format to use 64-bit relocations for the function address and properly align all entries.

This commit updates the stackmap format to version 1 to indicate the
reorganizaion of several fields. This was done in order to align stackmap
entries to their natural alignment and to minimize padding.

Fixes <rdar://problem/16005902>

llvm-svn: 205254