Migrate `branch-protection-check-IBT` to rmake.rs
- The Makefile version *never* ran because of Makefile syntax confusion because `ifeq ($(filter x86,$(LLVM_COMPONENTS)),x86_64)` [compares `x86` to `x86_64`, which always evaluates to false](https://github.com/rust-lang/rust/pull/126720#discussion_r1646808973).
- The test would've always failed because precompiled std is not built with `-Z cf-protection=branch`, but linkers require all input object files to indicate IBT support in order to enable IBT for the executable, which is not the case for std.
- Thus, the test input file is instead changed to a `no_std` program.
- The test is currently limited to only `x86_64-unknown-linux-gnu` host, there are various other problems when the test is cross-compiled that I didn't want to fix atm, and is left as an exercise for the `-Z cf-protection` implementers.
The GNU property note was added by #110304 in order to address #103001.
Partially supersedes #129156.
The rmake.rs port was initially authored by `@Rejyr` in #126720.
This PR is co-authored with `@Oneirical` and `@Rejyr.`
r? `@bjorn3` or reroll
try-job: x86_64-mingw-1
try-job: x86_64-mingw-2
try-job: x86_64-msvc
try-job: x86_64-apple-1
try-job: x86_64-apple-2
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