make: Replace deprecated emcc configuration

EXTRA_EXPORTED_RUNTIME_METHODS is deprecated. Replace with
EXPORTED_RUNTIME_METHODS.
2 jobs for master in 2 minutes and 42 seconds (queued for 29 seconds)
Child pipeline (parent)
Status Name Job ID Coverage
  Build
passed build:js #13575

00:01:39

 
  Test
passed test:js #13576

00:01:02