[OPENMP]Fix PR46146: Do not consider globalized variables as NRVO candidates.

[OPENMP]Fix PR46146: Do not consider globalized variables as NRVO candidates.

Summary:
If the variables must be globalized in OpenMP mode (local automatic
variable, GPU compilation mode, the variable may escape its declaration
context by the reference or by the pointer), it should not be considered
as the NRVO candidate. Otherwise, incorrect the return value of the
function might not be updated.

Reviewers: jdoerfert

Subscribers: yaxunl, guansong, sstefan1, cfe-commits, caomhin

Tags: #clang

Differential Revision: https://reviews.llvm.org/D80936