fix validation

Author: Thorsten Schütt

llvm/test/CodeGen/AArch64/GlobalISel/legalizer-info-validation.mir

@@ -665,7 +665,7 @@
 # DEBUG-NEXT: G_SPLAT_VECTOR (opcode {{[0-9]+}}): 2 type indices, 0 imm indices
 # DEBUG-NEXT: .. type index coverage check SKIPPED: no rules defined
 # DEBUG-NEXT: .. imm index coverage check SKIPPED: no rules defined
-# DEBUG-NEXT: G_STEP_VECTOR (opcode 236): 2 type indices, 0 imm indices
+# DEBUG-NEXT: G_STEP_VECTOR (opcode {{[0-9]+}}): 1 type index, 0 imm indices
 # DEBUG-NEXT: .. type index coverage check SKIPPED: no rules defined
 # DEBUG-NEXT: .. imm index coverage check SKIPPED: no rules defined
 # DEBUG-NEXT: G_VECTOR_COMPRESS (opcode {{[0-9]+}}): 2 type indices, 0 imm indices