Add suppression for recent nightly

See rust-lang/rust#148765.

Author: purplesyringa

suppressions/rust-1.93

@@ -0,0 +1,15 @@
+{
+   Rust 1.93 standard library
+   Memcheck:Leak
+   match-leak-kinds: possible
+   fun:malloc
+   fun:alloc
+   fun:alloc_impl
+   fun:allocate
+   fun:{closure#0}<std::thread::thread::Inner, std::alloc::System>
+   fun:allocate_for_layout<core::mem::maybe_uninit::MaybeUninit<std::thread::thread::Inner>, alloc::sync::{impl#*}::new_uninit_in::{closure_env#0}<std::thread::thread::Inner, std::alloc::System>, fn(*mut u8) -> *mut alloc::sync::ArcInner<core::mem::maybe_uninit::MaybeUninit<std::thread::thread::Inner>>>
+   fun:new_uninit_in<std::thread::thread::Inner, std::alloc::System>
+   fun:_RNvMs_NtNtCsjSkZfQkjc54_3std6thread6threadNtB4_6Thread3new
+   fun:_RNvNtNtCsjSkZfQkjc54_3std6thread7current12init_current
+   fun:current_or_unnamed
+}