Available SDKs Should Return the Empty List if Xcode is Not Installed

https://bugs.webkit.org/show_bug.cgi?id=259514
rdar://112870698

Reviewed by Alexey Proskuryakov.

If Xcode is not installed, webkitpy’s PlatformInfo#available_sdks method should return the empty list.

* Tools/Scripts/webkitpy/common/system/platforminfo.py:
(PlatformInfo.available_sdks):

Canonical link: https://commits.webkit.org/266325@main

Tools/Scripts/webkitpy/common/system/platforminfo.py

@@ -214,7 +214,13 @@ def available_sdks(self):
             return []
 
         XCODE_SDK_REGEX = re.compile(r'\-sdk (?P<sdk>\D+)\d+\.\d+(?P<specifier>\D*)')
-        output = self._executive.run_command(['xcodebuild', '-showsdks'], return_stderr=False)
+
+        output = ''
+
+        try:
+            output = self._executive.run_command(['xcodebuild', '-showsdks'], return_stderr=False)
+        except ScriptError:
+            return []
 
         sdks = list()
         for line in output.splitlines():