Some maintenance on implementation and tests:
* Drop manual TargetMachineBuilder setup
* Drop addDebugSupport() in favor of Orc's enableDebuggerSupport()
* Check that debug support plugins append jit_code_entry
* Update and reduce sample input
https://github.com/llvm/llvm-project/pull/74764 reported that the
`lljit-with-remote-debugging` test fails on AArch64 hosts, because the
input IR file states arch x86_64 explicitly. In order to drop the target
triple we have to remove a check in the example implementation.
Not sure it's fully portable now, but at least it's better than before.
The example demonstrates how to use a module summary index file produced for ThinLTO to:
* find the module that defines the main entry point
* find all extra modules that are required for the build
A LIT test runs the example as part of the LLVM test suite [1] and shows how to create a module summary index file.
The code also provides two Error types that can be useful when working with ThinLTO summaries.
[1] if LLVM_BUILD_EXAMPLES=ON and platform is not Windows
Differential Revision: https://reviews.llvm.org/D85974
