Update PHP extensions for Linux and Darwin

config/source.json

@@ -771,8 +771,9 @@
         ]
     },
     "libwebp": {
-        "type": "url",
-        "url": "https://github.com/webmproject/libwebp/archive/refs/tags/v1.3.2.tar.gz",
+        "type": "ghtagtar",
+        "repo": "webmproject/libwebp",
+        "match": "v1\\.\\d+\\.\\d+$",
         "provide-pre-built": true,
         "license": {
             "type": "file",
@@ -780,8 +781,10 @@
         }
     },
     "libxml2": {
-        "type": "url",
-        "url": "https://github.com/GNOME/libxml2/archive/refs/tags/v2.12.5.tar.gz",
+        "type": "ghtagtar",
+        "repo": "GNOME/libxml2",
+        "match": "v2\\.\\d+\\.\\d+$",
+        "provide-pre-built": false,
         "license": {
             "type": "file",
             "path": "Copyright"

src/globals/test-extensions.php

@@ -50,14 +50,14 @@ $prefer_pre_built = false;
 
 // If you want to test your added extensions and libs, add below (comma separated, example `bcmath,openssl`).
 $extensions = match (PHP_OS_FAMILY) {
-    'Linux', 'Darwin' => 'bcmath',
+    'Linux', 'Darwin' => 'bcmath,xsl,xml',
     'Windows' => 'bcmath',
 };
 
 // If you want to test shared extensions, add them below (comma separated, example `bcmath,openssl`).
 $shared_extensions = match (PHP_OS_FAMILY) {
-    'Linux' => 'pcov',
-    'Darwin' => 'pcov',
+    'Linux' => '',
+    'Darwin' => '',
     'Windows' => '',
 };