embind: Ensure embind works under c++11.

We no longer need to test c++17 since that is the default used, but we
should ensure we maintain compatibility with c++11.

Author: brendandahl

test/test_other.py

@@ -2972,8 +2972,8 @@ def test_embind_closure_no_dynamic_execution(self):
   })
   @parameterized({
     '': [],
-    # Ensure embind compiles under C++17 where "noexcept" became part of the function signature.
-    'cxx17': ['-std=c++17'],
+    # Ensure embind compiles under C++11 which is the miniumum supported version.
+    'cxx11': ['-std=c++11'],
     'o1': ['-O1'],
     'o2': ['-O2'],
     'o2_mem_growth': ['-O2', '-sALLOW_MEMORY_GROWTH', test_file('embind/isMemoryGrowthEnabled=true.cpp')],