Fix failing test_closure_full_js_library. NFC (#19050)

This should really have been part of #19044 but I landed it without
waiting for all tests to pass.

Author: sbc100

embuilder.py

@@ -86,6 +86,7 @@
     'libdlmalloc-mt',
     'libGL-emu',
     'libGL-mt',
+    'libGL-mt-emu',
     'libsockets_proxy',
     'libsockets-mt',
     'crtbegin',

test/test_other.py

@@ -8638,6 +8638,7 @@ def test_full_js_library_no_exception_throwing(self):
   def test_full_js_library_minimal_runtime(self):
     self.run_process([EMCC, test_file('hello_world.c'), '-sSTRICT_JS', '-sINCLUDE_FULL_LIBRARY', '-sMINIMAL_RUNTIME'])
 
+  @crossplatform
   @parameterized({
     '': [[]],
     # bigint support is interesting to test here because it changes which