tests/run-make-cargo/same-crate-name-and-macro-name: New regression test

[Enselic]

Closes #71259 which just E-needs-test. See #71259 (comment) for a good description of what we should test (which we do in this PR).

The project we add fails with an old nightly without the fix:

$ cargo +nightly-2020-03-10 run
   Compiling consumer v0.1.0 (/home/martin/src/rust-same-crate-same-macro/tests/run-make-cargo/same-crate-name-and-macro-name/consumer)
    Finished dev [unoptimized + debuginfo] target(s) in 0.14s
     Running `target/debug/consumer`
thread 'main' panicked at 'assertion failed: `(left == right)`
  left: `"version 1"`,
 right: `"version 2"`', src/main.rs:6:5
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace

and passes with a recent toolchain:

$ cargo run
warning: /home/martin/src/rust-same-crate-same-macro/tests/run-make-cargo/same-crate-name-and-macro-name/consumer/Cargo.toml: no edition set: defaulting to the 2015 edition while the latest is 2024
warning: /home/martin/src/rust-same-crate-same-macro/tests/run-make-cargo/same-crate-name-and-macro-name/mylib_v1/Cargo.toml: no edition set: defaulting to the 2015 edition while the latest is 2024
warning: /home/martin/src/rust-same-crate-same-macro/tests/run-make-cargo/same-crate-name-and-macro-name/mylib_v2/Cargo.toml: no edition set: defaulting to the 2015 edition while the latest is 2024
   Compiling mylib v2.0.0 (/home/martin/src/rust-same-crate-same-macro/tests/run-make-cargo/same-crate-name-and-macro-name/mylib_v2)
   Compiling mylib v1.0.0 (/home/martin/src/rust-same-crate-same-macro/tests/run-make-cargo/same-crate-name-and-macro-name/mylib_v1)
   Compiling consumer v0.1.0 (/home/martin/src/rust-same-crate-same-macro/tests/run-make-cargo/same-crate-name-and-macro-name/consumer)
    Finished `dev` profile [unoptimized + debuginfo] target(s) in 0.14s
     Running `target/debug/consumer`

in other words, the test tests what it should and will catch regressions.

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