Revert "Revert "Remove all usage of the global LLVMContextRef""

This reverts commit 541c657a738006d78171aa261125a6a46f283b35.
Revert "Revert "Have JIT execution take ownership of the LLVMContextRef""

This reverts commit 19adece68b00bd1873499cca6f1537750608d769.
Correctly parse commands for rusti

Closes #7120
Don't run passes again on JIT code

These passes are already run beforehand, no need to do them twice.
Resolve LLVM crashing in rustpkg tests
Try to fix a periodic windows build failure due to broken rwildcard macro
Start building a multithreaded LLVM
Upgrade LLVM
Fix build issues once LLVM has been upgraded

* LLVM now has a C interface to LLVMBuildAtomicRMW
* The exception handling support for the JIT seems to have been dropped
* Various interfaces have been added or headers have changed
Fix setting the fixed stack segment attribute on LLVM functions

At the same time create a more robust wrapper to try to prevent this type of
issue from cropping up in the future.
Updating LLVM again