Bootstrap command refactoring: improve debuggability (step 5)
Continuation of https://github.com/rust-lang/rust/pull/127321.
This PR improves the debuggability of command execution, by improving the output logged when a command fails (it now includes the exact location where the command was created and where it was executed), and also by adding a "drop bomb", which will panic if a command was created, but not executed (which is probably a bug).
Here is how the output of a failed command looks like:
```
Command "git" "foo" "[bar]" (failure_mode=Exit, stdout_mode=Capture, stderr_mode=Capture) did not execute successfully.
Expected success, got exit status: 1
Created at: src/core/build_steps/compile.rs:1699:9
Executed at: src/core/build_steps/compile.rs:1699:58
STDOUT ----
STDERR ----
git: 'foo' is not a git command. See 'git --help'.
```
And this is what is printed if you forget to execute a command:
```
thread 'main' panicked at /projects/personal/rust/rust/src/tools/build_helper/src/drop_bomb/mod.rs:42:13:
command constructed at `src/core/build_steps/compile.rs:1699:9` was dropped without being executed: `git`
```
Best reviewed commit by commit.
Tracking issue: https://github.com/rust-lang/rust/issues/126819
r? `@onur-ozkan`
c1e3f03e60