[flang][driver] rename flang-new to flang (#110023)

This does a global rename from `flang-new` to `flang`. I also
removed/changed any TODOs that I found related to making this change.

---------

Co-authored-by: H. Vetinari <[email protected]>
Co-authored-by: Andrzej Warzynski <[email protected]>

Author: 3 people

.github/workflows/release-binaries.yml

@@ -328,7 +328,7 @@ jobs:
       run: |
         # Build some of the mlir tools that take a long time to link
         if [ "${{ needs.prepare.outputs.build-flang }}" = "true" ]; then
-          ninja -C ${{ steps.setup-stage.outputs.build-prefix }}/build/tools/clang/stage2-bins/ -j2 flang-new bbc
+          ninja -C ${{ steps.setup-stage.outputs.build-prefix }}/build/tools/clang/stage2-bins/ -j2 flang bbc
         fi
         ninja -C ${{ steps.setup-stage.outputs.build-prefix }}/build/tools/clang/stage2-bins/ \
             mlir-bytecode-parser-fuzzer \

clang/include/clang/Basic/DiagnosticDriverKinds.td

@@ -147,6 +147,9 @@ def warn_drv_unsupported_option_for_processor : Warning<
 def warn_drv_unsupported_openmp_library : Warning<
   "the library '%0=%1' is not supported, OpenMP will not be enabled">,
   InGroup<OptionIgnored>;
+def warn_openmp_experimental : Warning<
+  "OpenMP support in flang is still experimental">,
+  InGroup<ExperimentalOption>;
 
 def err_drv_invalid_thread_model_for_target : Error<
   "invalid thread model '%0' in '%1' for this target">;