* cross-platform wrapper around memory-backed memorymappedfile creation

* reenable FCS tests on non-windows platforms

* publish test results on non-windows platforms

* ensure correct .net sdk versions are installed regardless of VM image preloads

* simple workaround for missing mscorlib versions to TFMs

* publish per-framework xml results and report them in AZDO

* rework mono fixes to use ByteArrayMemory directly

* move runningOnMono call to bytes.fs and patch up callsites

* revert to build-only on mono-containing platforms

another MR will be required to fix the underlying logic before those can be changed to run tests again

* trigger ci