fix: xArgs command update (#2095)

Fixes #1538 

A small update to use a default option instead of failing straight out if the maxArgs is reached.

## Checklist
- [x] Integration tests updated

test_runner/src/main/kotlin/ftl/ios/xctest/common/ParseSwiftTests.kt

@@ -16,11 +16,11 @@ internal fun parseSwiftTests(binary: String): List<String> {
     // getconf ARG_MAX
     // Windows has different limits
     val argMax = if (isWindows) 250_36 else 262_144
-
+    val xargsOption = binary.quote().determineXArgsCommand(argMax)
     val cmd = when {
-        isMacOS -> "nm -gU ${binary.quote()} | xargs -s $argMax xcrun swift-demangle"
-        isLinux -> "export LD_LIBRARY_PATH=~/.flank; export PATH=~/.flank:\$PATH; nm -gU ${binary.quote()} | xargs -s $argMax swift-demangle"
-        isWindows -> "llvm-nm.exe -gU ${binary.quote().replace("\\", "/")} | xargs.exe -s $argMax swift-demangle.exe"
+        isMacOS -> "nm -gU ${binary.quote()} | xargs $xargsOption xcrun swift-demangle"
+        isLinux -> "export LD_LIBRARY_PATH=~/.flank; export PATH=~/.flank:\$PATH; nm -gU ${binary.quote()} | xargs $xargsOption swift-demangle"
+        isWindows -> "llvm-nm.exe -gU ${binary.quote().replace("\\", "/")} | xargs.exe $xargsOption swift-demangle.exe"
         else -> throw RuntimeException("Unsupported OS for Integration Tests")
     }
 
@@ -45,3 +45,10 @@ internal fun parseSwiftTests(binary: String): List<String> {
     }
     return results.distinct()
 }
+
+private fun String.determineXArgsCommand(argsMax: Int) = if (this.length > argsMax) {
+    println("WARNING: The amount of characters has exceeded the OS threshold for xArgs. -n1 will be used to ensure the command completes successfully. It may increase completion time substantially.")
+    "-n1"
+} else {
+    "-s $argsMax"
+}