[circt-verilog-lsp] Mark test as unsupported by Valgrind, NFC

Author: uenoku

test/Tools/circt-verilog-lsp-server/command-files.test

@@ -1,5 +1,7 @@
 // RUN: cd %S && circt-verilog-lsp-server -lit-test -C %S/include/filelist.f < %s | FileCheck %s
 // REQUIRES: slang
+// Avoid Slang-internal valgrind errors about 'Conditional jump or move depends on uninitialised value(s)'.
+// UNSUPPORTED: valgrind
 {"jsonrpc":"2.0","id":0,"method":"initialize","params":{"processId":123,"rootPath":"verilog","capabilities":{},"trace":"off"}}
 // -----
 {"jsonrpc":"2.0","method":"textDocument/didOpen","params":{"textDocument":{