fix: test: PHP 8.2 incompatibility

Author: zeriyoshi

ext/random/tests/02_engine/z_serialize.phpt

@@ -38,7 +38,7 @@ foreach ($engines as $engine) {
     for ($i = 0; $i < 5000; $i++) {
         if ($engine->generate() !== $engine2->generate()) {
             $className = $engine::class;
-            die("failure class: ${className} i: ${i}");
+            die("failure class: {$className} i: {$i}");
         }
     }
 }

ext/random/tests/03_randomizer/compatibility_user.phpt

@@ -10,7 +10,7 @@ for ($i = 0; $i < 1000; $i++) {
     $native = $native_randomizer->getInt();
     $user = $user_randomizer->getInt();
     if ($native !== $user) {
-        die("failure CombinedLCG i: ${i} native: ${native} user: ${user}");
+        die("failure CombinedLCG i: {$i} native: {$native} user: {$user}");
     }
 }
 
@@ -21,7 +21,7 @@ for ($i = 0; $i < 1000; $i++) {
     $native = $native_randomizer->getInt();
     $user = $user_randomizer->getInt();
     if ($native !== $user) {
-        die("failure MersenneTwister i: ${i} native: ${native} user: ${user}");
+        die("failure MersenneTwister i: {$i} native: {$native} user: {$user}");
     }
 }
 
@@ -32,7 +32,7 @@ for ($i = 0; $i < 1000; $i++) {
     $native = $native_randomizer->getInt();
     $user = $user_randomizer->getInt();
     if ($native !== $user) {
-        die("failure PCG64 i: ${i} native: ${native} user: ${user}");
+        die("failure PCG64 i: {$i} native: {$native} user: {$user}");
     }
 }