git: openjdk/wakefield: created branch pure_wl_toolkit_21 based on the branch X11_compatibility_doc containing 10 unique commits

[duke]

The following commits are unique to the pure_wl_toolkit_21 branch:
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76cda9f4: 8255548: Missing coverage for javax.xml.crypto.dom.DOMCryptoContext
8a1639d4: 8305936: JavaThread::create_system_thread_object has unused is_visible argument
287bb06d: 8305902: (cs) Resolve default Charset only once in StreamEncoder and StreamDecoder
12358e6c: 8305934: PPC64: Disable VMContinuations on Big Endian
3651b922: 8305944: assert(is_aligned(ref, HeapWordSize)) failed: invariant
c0c31224: 8305618: Move gcold out of tier1
0826ceee: 8301495: Replace NULL with nullptr in cpu/ppc
54bf3700: 8170945: Collectors$Partition should override more Map methods
d2ce04bb: 8301496: Replace NULL with nullptr in cpu/riscv
36c80e07: Initial version of WLToolkit and Vulkan support