MIRParser/MIRPrinter: Compute isSSA instead of printing/parsing it.

Specifying isSSA is an extra line at best and results in invalid MI at
worst. Compute the value instead.

Differential Revision: http://reviews.llvm.org/D22722

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@279600 91177308-0d34-0410-b5e6-96231b3b80d8
70 files changed