feat(disasm): name the CLDEMOTE encoding the decoder refuses

The hint NOP opcode 0F 1C /r with a memory operand is CLDEMOTE, a
memory-only instruction the toolchain's own table carries; the decoder
rejects the encoding instead of naming it.  The rejected-encoding side
of the supplementary table names it from the bytes, and the corpus row
0f1c03 pins the text in the unlisted fixture, round trip byte exact.

Assisted-by: GLM 5.3 Flash

disasm/naming_amd64.go

@@ -318,3 +318,24 @@ func nameAMD64Endbr(p amd64Prefixes, tail []byte) (string, int, bool) {
 	}
 	return "", 0, false
 }
+
+// nameAMD64Rejected names an amd64 encoding the decoder refuses outright,
+// one family at a time as the corpus rows land.  CLDEMOTE, NP 0F 1C /r
+// with a memory operand, is the first: the toolchain's own table carries
+// it as a memory-only instruction, and the decoder rejects the encoding
+// instead of naming it.  The register forms of the same opcode are the
+// hint NOPs the corpus does not spell, and they stay rejected.
+func nameAMD64Rejected(code []byte) (string, int, bool) {
+	p, ok := scanAMD64Prefixes(code)
+	if !ok || p.osz || p.rep || p.repne {
+		return "", 0, false
+	}
+	if len(code) < p.n+3 || code[p.n] != 0x0f || code[p.n+1] != 0x1c {
+		return "", 0, false
+	}
+	rm, ok := decodeAMD64RM(code[p.n+2:], p.rexR, p.rexX, p.rexB)
+	if !ok || rm.regForm {
+		return "", 0, false
+	}
+	return "CLDEMOTE " + rm.text(), p.n + 2 + rm.n, true
+}