Upgrade Rust toolchain to nightly-2024-02-25

[adpaco-aws]

Upgrades the Rust toolchain to nightly-2024-02-25. The Rust compiler PRs that triggered changes in this upgrades are:

• Make CodegenBackend::join_codegen infallible. rust-lang/rust#121209
• Make intrinsic fallback bodies cross-crate inlineable rust-lang/rust#121309
• Use intrinsics::debug_assertions in debug_assert_nounwind rust-lang/rust#120863
• Tracking import use types for more accurate redundant import checking rust-lang/rust#117772
• rename ptr::invalid -> ptr::without_provenance rust-lang/rust#117658

With rust-lang/rust#121309 some intrinsics became inlineable so their names became qualified. This made our match on the intrinsic name to fail in those cases, leaving them as unsupported constructs as in this example:

warning: Found the following unsupported constructs:
             - _RNvNtCscyGW2MM2t5j_4core10intrinsics8unlikelyCs1eohKeNmpdS_5arith (3)
             - caller_location (1)
             - foreign function (1)
         
         Verification will fail if one or more of these constructs is reachable.
         See https://model-checking.github.io/kani/rust-feature-support.html for more details.

[...]

Failed Checks: _RNvNtCscyGW2MM2t5j_4core10intrinsics8unlikelyCs1eohKeNmpdS_5arith is not currently supported by Kani. Please post your example at https://github.com/model-checking/kani/issues/new/choose
 File: "/home/ubuntu/.rustup/toolchains/nightly-2024-02-18-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/core/src/num/mod.rs", line 25, in core::num::<impl i8>::checked_add

We use trimmed_name() to work around this, but that may include type arguments if the intrinsic is defined on generics. So in those cases, we just take the first part of the name so we can keep the rest as before.

Resolves #3044

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 and MIT licenses.