Flatten nested setup_call_cleanup calls in tests

Replace nested setup_call_cleanup/3 calls with compound goals
in setup and cleanup arguments, following Triska's feedback.

Changed pattern from:
  setup_call_cleanup(A, setup_call_cleanup(B, Goal, close(Y)), close(X))

To:
  setup_call_cleanup((A,B), Goal, (close(Y), close(X)))

Applied to tests 1-3 in src/tests/get_n_chars.pl.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

Author: jjtolton

src/tests/get_n_chars.pl

@@ -11,17 +11,15 @@
     atom_chars('/bin/echo', Echo),
     atom_chars('ABCDEFGHIJ', Content),
     iso_ext:setup_call_cleanup(
-        process:process_create(Echo, [Content], [stdout(pipe(Out1))]),
-        iso_ext:setup_call_cleanup(
-            process:process_create(Echo, [Content], [stdout(pipe(Out2))]),
-            (
-                charsio:get_n_chars(Out1, 5, Chars1),
-                charsio:get_n_chars(Out2, 5, Chars2, 0),
-                Chars1 = Chars2
-            ),
-            close(Out2)
+        ( process:process_create(Echo, [Content], [stdout(pipe(Out1))]),
+          process:process_create(Echo, [Content], [stdout(pipe(Out2))]) ),
+        (
+            charsio:get_n_chars(Out1, 5, Chars1),
+            charsio:get_n_chars(Out2, 5, Chars2, 0),
+            Chars1 = Chars2
         ),
-        close(Out1)
+        ( close(Out2),
+          close(Out1) )
     )
 )).
 
@@ -30,20 +28,18 @@
     atom_chars('/bin/echo', Echo),
     atom_chars('Testing', Content),
     iso_ext:setup_call_cleanup(
-        process:process_create(Echo, [Content], [stdout(pipe(Out1))]),
-        iso_ext:setup_call_cleanup(
-            process:process_create(Echo, [Content], [stdout(pipe(Out2))]),
-            (
-                charsio:get_n_chars(Out1, N1, Chars1),
-                charsio:get_n_chars(Out2, N2, Chars2, 0),
-                N1 = N2,
-                Chars1 = Chars2,
-                N1 = 8,
-                Chars1 = "Testing\n"
-            ),
-            close(Out2)
+        ( process:process_create(Echo, [Content], [stdout(pipe(Out1))]),
+          process:process_create(Echo, [Content], [stdout(pipe(Out2))]) ),
+        (
+            charsio:get_n_chars(Out1, N1, Chars1),
+            charsio:get_n_chars(Out2, N2, Chars2, 0),
+            N1 = N2,
+            Chars1 = Chars2,
+            N1 = 8,
+            Chars1 = "Testing\n"
         ),
-        close(Out1)
+        ( close(Out2),
+          close(Out1) )
     )
 )).
 
@@ -52,18 +48,16 @@
     atom_chars('/bin/echo', Echo),
     atom_chars('NegativeTest', Content),
     iso_ext:setup_call_cleanup(
-        process:process_create(Echo, [Content], [stdout(pipe(Out1))]),
-        iso_ext:setup_call_cleanup(
-            process:process_create(Echo, [Content], [stdout(pipe(Out2))]),
-            (
-                charsio:get_n_chars(Out1, N1, Chars1),
-                charsio:get_n_chars(Out2, N2, Chars2, -100),
-                N1 = N2,
-                Chars1 = Chars2
-            ),
-            close(Out2)
+        ( process:process_create(Echo, [Content], [stdout(pipe(Out1))]),
+          process:process_create(Echo, [Content], [stdout(pipe(Out2))]) ),
+        (
+            charsio:get_n_chars(Out1, N1, Chars1),
+            charsio:get_n_chars(Out2, N2, Chars2, -100),
+            N1 = N2,
+            Chars1 = Chars2
         ),
-        close(Out1)
+        ( close(Out2),
+          close(Out1) )
     )
 )).