Remove old PHP extension (#7695)

* Removed references to legacy class names from generated code.

* Removed old PHP extension in favor of new extension. This drops PHP5 compat.

* Updated failure lists for things fixed by the new extension.

* Updated Makefile.am for new file list.

* Fix distcheck.

php/tests/compile_extension.sh

diff --git a/php/tests/compile_extension.sh b/php/tests/compile_extension.sh
index 37c6810..5834249 100755
--- a/php/tests/compile_extension.sh
+++ b/php/tests/compile_extension.sh
@@ -12,18 +12,9 @@
   CFLAGS="-g -O0 -Wall"
 fi
 
-
 pushd  ../ext/google/protobuf
 phpize --clean
 rm -f configure.in configure.ac
+php make-preload.php
 phpize && ./configure --with-php-config=$(which php-config) CFLAGS="$CFLAGS" && make
 popd
-
-if [ $(php -r "echo PHP_VERSION;" | cut -c1) != "5" ]; then
-  pushd  ../ext/google/protobuf2
-  phpize --clean
-  rm -f configure.in configure.ac
-  php make-preload.php
-  phpize && ./configure --with-php-config=$(which php-config) CFLAGS="$CFLAGS" && make
-  popd
-fi

php/tests/php_implementation_test.php

diff --git a/php/tests/php_implementation_test.php b/php/tests/php_implementation_test.php
index 307b749..db3c361 100644
--- a/php/tests/php_implementation_test.php
+++ b/php/tests/php_implementation_test.php
@@ -538,7 +538,7 @@
 
     /**
      * @expectedException Exception
-     * @expectedExceptionMessage Expect Foo\TestMessage_Sub.
+     * @expectedExceptionMessage Expect Foo\TestMessage\Sub.
      */
     public function testArraysForMessagesThrowsException()
     {

php/tests/test.sh

diff --git a/php/tests/test.sh b/php/tests/test.sh
index b1d8d5f..b10b57f 100755
--- a/php/tests/test.sh
+++ b/php/tests/test.sh
@@ -8,14 +8,9 @@
 ./compile_extension.sh
 
 PHP_VERSION=$(php -r "echo PHP_VERSION;")
-TEST_NEW_EXTENSION=true
 
 # Each version of PHPUnit supports a fairly narrow range of PHP versions.
 case "$PHP_VERSION" in
-  5.*.*)
-    PHPUNIT=phpunit-5.6.8.phar
-    TEST_NEW_EXTENSION=false
-    ;;
   7.0.*|7.1.*|7.2.*)
     # Oddly older than for 5.6. Not sure the reason.
     PHPUNIT=phpunit-5.6.0.phar
@@ -24,7 +19,7 @@
     PHPUNIT=phpunit-8.phar
     ;;
   *)
-    echo "ERROR: Unknown PHP version $PHP_VERSION"
+    echo "ERROR: Unsupported PHP version $PHP_VERSION"
     exit 1
     ;;
 esac
@@ -39,9 +34,6 @@
   echo "* $t"
   echo "****************************"
   php -dextension=../ext/google/protobuf/modules/protobuf.so $PHPUNIT --bootstrap autoload.php $t
-  if [ "$TEST_NEW_EXTENSION" = "true" ]; then
-    php -dextension=../ext/google/protobuf2/modules/protobuf.so $PHPUNIT --bootstrap autoload.php $t
-  fi
   echo ""
 done
 
@@ -51,9 +43,6 @@
   echo "* $t persistent"
   echo "****************************"
   php -d protobuf.keep_descriptor_pool_after_request=1 -dextension=../ext/google/protobuf/modules/protobuf.so $PHPUNIT --bootstrap autoload.php $t
-  if [ "$TEST_NEW_EXTENSION" = "true" ]; then
-    php -d protobuf.keep_descriptor_pool_after_request=1 -dextension=../ext/google/protobuf2/modules/protobuf.so $PHPUNIT --bootstrap autoload.php $t
-  fi
   echo ""
 done
 
@@ -64,10 +53,6 @@
 export USE_ZEND_ALLOC=0
 valgrind --leak-check=yes php -dextension=../ext/google/protobuf/modules/protobuf.so memory_leak_test.php
 valgrind --leak-check=yes php -d protobuf.keep_descriptor_pool_after_request=1 -dextension=../ext/google/protobuf/modules/protobuf.so memory_leak_test.php
-if [ "$TEST_NEW_EXTENSION" = "true" ]; then
-  valgrind --leak-check=yes php -dextension=../ext/google/protobuf2/modules/protobuf.so memory_leak_test.php
-  valgrind --leak-check=yes php -d protobuf.keep_descriptor_pool_after_request=1 -dextension=../ext/google/protobuf2/modules/protobuf.so memory_leak_test.php
-fi
 
 # TODO(teboring): Only for debug (phpunit has memory leak which blocks this beging used by
 # regresssion test.)