[PHP tests] Remove non-standard PHP memory leak test (grpc#34257)

This test is not giving us good signals while adding some long term
maintenance cost. The way the test is set up and run was not standard.
There are other sanitizer tests to test for memory leaks.

Author: stanley-cheung

src/php/bin/run_tests.sh

@@ -38,22 +38,3 @@ if [[ "$SKIP_PERSISTENT_CHANNEL_TESTS" != "true" ]]; then
    $(which php) $extension_dir -d max_execution_time=300 $(which phpunit) -v --debug \
      ../tests/unit_tests/PersistentChannelTests
 fi
-
-export ZEND_DONT_UNLOAD_MODULES=1
-export USE_ZEND_ALLOC=0
-# Detect whether valgrind is executable
-if [ -x "$(command -v valgrind)" ]; then
-  # skip the memory leak test on ARM64
-  # TODO(jtattermusch): reenable the test once https://github.com/grpc/grpc/issues/29098 is fixed.
-  if [ "$(uname -m)" != "aarch64" ]; then
-    $(which valgrind) --error-exitcode=10 --leak-check=yes \
-      --errors-for-leak-kinds=definite \
-      -v \
-      --num-callers=30 \
-      --suppressions=../tests/MemoryLeakTest/ignore_leaks.supp \
-      $VALGRIND_UNDEF_VALUE_ERRORS \
-      $(which php) $extension_dir -d max_execution_time=300 \
-      ../tests/MemoryLeakTest/MemoryLeakTest.php
-  fi
-fi
-