Rebaseline codesize tests. NFC

Warn if EXPORTED_FUNCTIONS is used with MAIN_MODULE=1/SIDE_MODULE=1 (e…

…mscripten-core#10075)

This doesn't make sense since these imply all symbols are already
exported.

Avoid 'pre-FOO' temp files, which are duplicates (emscripten-core#15920)

I noticed this while debugging. The files end up like this:

emcc-8-FOO
emcc-9-pre-BAR

The pre of bar is identical to the one from after foo. This PR just makes us
consistently always save a temp file afterwards.

Initial usage of ES6 in JS library code (emscripten-core#15765)

Now that ES6 features are permitted in emscripten JS library
code (see emscripten-core#15763) we can take advantage of some of them to
reduce size of our output JS.

This is just an initial test of using ES6 features.

See: emscripten-core#11984

Remove 10 second sleep after test. NFC (emscripten-core#15810)

It seems this was mistakenly checked in as part of emscripten-core#14375.

Fix issue with embind function calls with pthreads enabled (emscripte…

…n-core#15561)

Remove tests/fuzz tests. NFC (emscripten-core#15420)

These made more sense when we were maintaining the compiler
backend (fastcomp) but these days such tests make more sense
in upstream llvm.

Remove zero-init of dynamic library static data/table region. NFC (em…

…scripten-core#15390)

As of https://reviews.llvm.org/D112667 that module itself will zero
its bcc data segment at the same time as loading int its non-bss
data.

For the table region, the loop was already needless since table.grow
will have filly the region with null entries already.

Add Emval.{toHandle, toValue} to changelog (emscripten-core#15328)

Fix broken links to emsdk (emscripten-core#15196)