Backport 3.3: YJIT memory leak fix with additional CI fixes

[XrXr]

This is a backport PR for https://bugs.ruby-lang.org/issues/20209
When we landed the singleton class fix on master, it revealed some unrelated panics with tailcalls which destabilized CI. So I'm making a PR to group everything together to keep the backport branch green.

---

YJIT: Avoid leaks by skipping objects with a singleton class

For receiver with a singleton class, there are multiple vectors YJIT can
end up retaining the object. There is a path in jit_guard_known_klass()
that bakes the receiver into the code, and the object could also be kept
alive indirectly through a path starting at the CME object baked into
the code.

To avoid these leaks, avoid compiling calls on objects with a singleton
class.

See: https://github.com/Shopify/ruby/issues/552

[Bug #20209]
---
 yjit/bindgen/src/main.rs       |  1 +
 yjit/src/codegen.rs            | 17 +++++++++++++++++
 yjit/src/cruby_bindings.inc.rs |  1 +
 yjit/src/stats.rs              |  2 ++
 4 files changed, 21 insertions(+)

YJIT: Fix tailcall and JIT entry eating up FINISH frames (#9729)

Suppose YJIT runs a rb_vm_opt_send_without_block()
fallback and the control frame stack looks like:

```
will_tailcall_bar [FINISH]
caller_that_used_fallback
```

will_tailcall_bar() runs in the interpreter and sets up a tailcall.
Right before JIT_EXEC() in the `send` instruction, the stack will look like:

```
bar [FINISH]
caller_that_used_fallback
```

Previously, JIT_EXEC() ran bar() in JIT code, which caused the `FINISH`
flag to return to the interpreter instead of to the JIT code running
caller_that_used_fallback(), causing code to run twice and probably
crash. Recent flaky failures on CI about "each stub expects a particular
iseq" are probably due to leaving methods twice in
`test_optimizations.rb`.

Only run JIT code from the interpreter if a new frame is pushed.
---
 test/ruby/test_optimization.rb | 11 +++++++++++
 vm_exec.h                      |  3 ++-
 2 files changed, 13 insertions(+), 1 deletion(-)

YJIT: No need to RESTORE_REG now that we reject tailcalls

Thanks to Kokubun for noticing.

Follow-up: b0711b1cf152afad0a480ee2f9bedd142a0d24ac
---
 vm_exec.h | 1 -
 1 file changed, 1 deletion(-)