[ELF] Improve INCLUDE cycle tests

And demonstrate the incorrect diagnostic when a linker script is
included multiple times (#93947).

Author: MaskRay

lld/test/ELF/linkerscript/include-cycle.s

@@ -1,15 +1,30 @@
 # REQUIRES: x86
-# RUN: llvm-mc -filetype=obj -triple=x86_64-unknown-linux %s -o %t.o
+# RUN: rm -rf %t && split-file %s %t && cd %t
+# RUN: llvm-mc -filetype=obj -triple=x86_64 a.s -o a.o
 
-# RUN: echo "INCLUDE \"%t1.script\"" > %t1.script
-# RUN: not ld.lld %t.o %t1.script 2>&1 | FileCheck %s
+# RUN: not ld.lld a.o -T 1.lds 2>&1 | FileCheck %s --check-prefix=ERR1
+# ERR1: error: 1.lds:1: there is a cycle in linker script INCLUDEs
 
-# RUN: echo "INCLUDE \"%t2.script\"" > %t1.script
-# RUN: echo "INCLUDE \"%t1.script\"" > %t2.script
-# RUN: not ld.lld %t.o %t1.script 2>&1 | FileCheck %s
+# RUN: not ld.lld a.o -T 2a.lds 2>&1 | FileCheck %s --check-prefix=ERR2
+# ERR2: error: 2a.lds:1: there is a cycle in linker script INCLUDEs
 
-# CHECK: there is a cycle in linker script INCLUDEs
+# RUN: not ld.lld a.o -T 3.lds 2>&1 | FileCheck %s --check-prefix=ERR3
+# ERR3: error: 3.lds:2: there is a cycle in linker script INCLUDEs
 
+#--- 0.lds
+BYTE(42)
+#--- 1.lds
+INCLUDE "1.lds"
+#--- 2a.lds
+INCLUDE "2b.lds"
+#--- 2b.lds
+INCLUDE "2a.lds"
+#--- 3.lds
+SECTIONS {
+  foo : { INCLUDE "0.lds" INCLUDE "0.lds" }
+}
+
+#--- a.s
 .globl _start
 _start:
   ret