Fix the ESNext build with disabled JERRY_BUILTIN_PROXY (#4320)

With a disabled JERRY_BUILTIN_PROXY option the build fails becouse
of missing guards.

The run-test buildoption_test is also extended with this.

JerryScript-DCO-1.0-Signed-off-by: Adam Kallai kadam@inf.u-szeged.hu

tools/run-tests.py

@@ -166,6 +166,8 @@ JERRY_BUILDOPTIONS = [
             ['--jerry-debugger=on']),
     Options('buildoption_test-module-off',
             ['--compile-flag=-DJERRY_MODULE_SYSTEM=0', '--lto=off']),
+    Options('buildoption_test-builtin-proxy-off',
+            ['--compile-flag=-DJERRY_BUILTIN_PROXY=0']),
 ]
 
 def get_arguments():