Check current thread in selected JRT_LEAF methods

With JDK-8275286, we added the `Thread::current()` checks for most of the JRT entries. But `JRT_LEAF` is still not checked, because not every `JRT_LEAF` carries a `JavaThread` argument. Having assertions there helps for two reasons. First, these methods can be called from the stub/compiler code, which might be erroneous with thread handling (especially in x86_32 that does not have a dedicated thread register). Second, in the post-Loom world, current thread can change suddenly, as evidenced here: https://mail.openjdk.org/pipermail/hotspot-compiler-dev/2022-November/060779.html.

We can add the thread checks to relevant `JRT_LEAF` methods that accept `JavaThread*` too.