Fix asan.test_openjpeg (#15112)

Since #15083, asan now sets `EXIT_RUNTIME` by default and this test
depends on being able to run a `postRun` handler.

Currently `postRun` handlers are not compatible with `EXIT_RUNTIME`
under node: #15080.

Author: sbc100

tests/test_core.py

@@ -6237,6 +6237,9 @@ def image_compare(output):
 
         return output
 
+      # Explictly disable EXIT_RUNTIME, since otherwise addOnPostRun does not work.
+      # https://github.com/emscripten-core/emscripten/issues/15080
+      self.set_setting('EXIT_RUNTIME', 0)
       self.emcc_args += ['--minify=0'] # to compare the versions
       self.emcc_args += ['--pre-js', 'pre.js']