minor #41295 Remove constraint for PHP < 8 (jderusse)

This PR was squashed before being merged into the 6.0 branch.

Discussion
----------

Remove constraint for PHP < 8

| Q             | A
| ------------- | ---
| Branch?       | 6.0
| Bug fix?      | no
| New feature?  | no
| Deprecations? | no
| Tickets       | -
| License       | MIT
| Doc PR        | -

Remove code check against PHP_VERSION < 8 (except for PHPUnit Bridge)

Commits
-------

a8c74ae3fb Remove constraint for PHP < 8

Author: nicolas-grekas

AbstractUnicodeString.php

@@ -191,7 +191,7 @@ public function folded(bool $compat = true): parent
     {
         $str = clone $this;
 
-        if (!$compat || \PHP_VERSION_ID < 70300 || !\defined('Normalizer::NFKC_CF')) {
+        if (!$compat || !\defined('Normalizer::NFKC_CF')) {
             $str->string = normalizer_normalize($str->string, $compat ? \Normalizer::NFKC : \Normalizer::NFC);
             $str->string = mb_strtolower(str_replace(self::FOLD_FROM, self::FOLD_TO, $this->string), 'UTF-8');
         } else {
@@ -427,10 +427,6 @@ public function upper(): parent
         $str = clone $this;
         $str->string = mb_strtoupper($str->string, 'UTF-8');
 
-        if (\PHP_VERSION_ID < 70300) {
-            $str->string = str_replace(self::UPPER_FROM, self::UPPER_TO, $str->string);
-        }
-
         return $str;
     }
 

LazyString.php

@@ -111,11 +111,6 @@ public function __toString()
                 $e = new \TypeError(sprintf('Return value of %s() passed to %s::fromCallable() must be of the type string, %s returned.', $callback, static::class, $type));
             }
 
-            if (\PHP_VERSION_ID < 70400) {
-                // leverage the ErrorHandler component with graceful fallback when it's not available
-                return trigger_error($e, \E_USER_ERROR);
-            }
-
             throw $e;
         }
     }

UnicodeString.php

@@ -268,9 +268,6 @@ public function slice(int $start = 0, int $length = null): AbstractString
     {
         $str = clone $this;
 
-        if (\PHP_VERSION_ID < 80000 && 0 > $start && grapheme_strlen($this->string) < -$start) {
-            $start = 0;
-        }
         $str->string = (string) grapheme_substr($this->string, $start, $length ?? 2147483647);
 
         return $str;
@@ -280,9 +277,6 @@ public function splice(string $replacement, int $start = 0, int $length = null):
     {
         $str = clone $this;
 
-        if (\PHP_VERSION_ID < 80000 && 0 > $start && grapheme_strlen($this->string) < -$start) {
-            $start = 0;
-        }
         $start = $start ? \strlen(grapheme_substr($this->string, 0, $start)) : 0;
         $length = $length ? \strlen(grapheme_substr($this->string, $start, $length ?? 2147483647)) : $length;
         $str->string = substr_replace($this->string, $replacement, $start, $length ?? 2147483647);