[HIP] Fix unbundling

HIP uses clang-offload-bundler to bundle intermediate files for host
and different gpu archs together. When a file is unbundled,
clang-offload-bundler should be called only once, and the objects
for host and different gpu archs should be passed to the next
jobs. This is because Driver maintains CachedResults which maps
triple-arch string to output files for each job.

This patch fixes a bug in Driver::BuildJobsForActionNoCache which
uses incorrect key for CachedResults for HIP which causes
clang-offload-bundler being called mutiple times and incorrect
output files being used.

It only affects HIP.

Differential Revision: https://reviews.llvm.org/D47555

llvm-svn: 334128