[OPENMP]Allow priority clause in combined task-based directives.

The expression of the priority clause must be captured in the combined
task-based directives, like 'parallel master taskloop' directive.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@375026 91177308-0d34-0410-b5e6-96231b3b80d8
8 files changed