Ensure EH/longjmp does not change code after link

We used to require Binaryen postprocessing for EH and longjmp and have
`fail` requirements for those features in
`other.test_immutable_after_link`. I deleted those requirements in
 emscripten-core#12399, but it could have been better if I didn't just delete them but
changed them to `ok` requirements. This PR adds them.

Author: aheejin

tests/test_other.py

@@ -9009,6 +9009,10 @@ def ok(args, filename='hello_world.cpp', expected='hello, world!'):
     ok(required_flags, filename='hello_world_main_loop.cpp')
     # -O1 is ok as we don't run wasm-opt there (but no higher, see below)
     ok(required_flags + ['-O1'])
+    # exception support shouldn't require change after linking
+    ok(required_flags + ['-fexceptions'])
+    # longjmp support shouldn't require change after linking
+    ok(required_flags + ['-sSUPPORT_LONGJMP=1'])
 
     # other builds fail with a standard message + extra details
     def fail(args, details):