[OpenMP][OMPT] Implement verbose tool loading

OpenMP 5.1 introduces the new env variable
OMP_TOOL_VERBOSE_INIT=(disabled|stdout|stderr|<filename>) to enable verbose
loading and initialization of OMPT tools.
This env variable helps to understand the cause when loading of a tool fails
(e.g., undefined symbols or dependency not in LD_LIBRARY_PATH)
Output of OMP_TOOL_VERBOSE_INIT is added for OMP_DISPLAY_ENV

Tests for this patch are integrated into the different existing tool loading
tests, making these tests more verbose. An Archer specific verbose test is
integrated into an existing Archer test.

Patch prepared by: Isabel Thärigen

Differential Revision: https://reviews.llvm.org/D91464

GitOrigin-RevId: b281a05dacb485d3c3c9cc7f7f5e8fb858ac67bc
6 files changed