version_70: Optimize normally with debug info (#1927)

* optimize normally with debug info - some of it may be removed, but that's the price of higher optimization levels, and by optimizing normally in profiling and -g2 etc. builds they are more comparable to normal ones, yielding better data
* copy debug locations automatically in replaceCurrent in wasm-traversal, so optimization passes at least by default will preserve debuggability

version_69: Dead return value elimination in DeadArgumentElimination (#1917)

* Finds functions whose return value is always dropped, and removes the return.
* Run multiple iterations of the pass, as one can enable others.
* Do not run DeadArgumentElimination at all if debug info is present (with these improvements, it became much more likely to destroy debug info).

Saves 2.5% on hello world, because of some simple libc calls.

1.38.28: NaN fuzzing improvements (#1913)

* make DE_NAN avoid creating nan literals in the first place
* add a reducer option `--denan` to not introduce nans in destructive reduction
* add a `Literal::isNaN()` method
* also remove the default exception logging from the fuzzer js glue, which is a source of non-useful VM differences (like nan nondeterminism)
* added an option `--no-fuzz-nans` to make it easy to avoid nans when fuzzing (without hacking the source and recompiling).

Background: trying to get fuzzing on jsc working despite this open issue: https://bugs.webkit.org/show_bug.cgi?id=175691

version_68

respect --no-validation in pass-debug mode (#1904)

1.38.27

legalize invokes even when doing minimal legalization, as js needs th…

1.38.26: Fix EM_ASM+pthreads (#1891)

To calculate the metadata, we must look at the segments. If we split them out earlier (which we do for threads), they aren't there.

version_67: Strip the producers section in --strip-producers (#1875)

WebAssembly/tool-conventions#93 has a summary of emscripten's current thinking on this. For Binaryen, we don't want to do anything to the producers section by default, but do want it to be possible to optionally remove it. To achieve that, this PR

 * creates a --strip-producers pass that removes that section.
 * creates a --strip-debug pass that removes debug info, same as the old --strip, which is still around but deprecated.

A followup in emscripten will use this pass by default.

version_66

wasm-emscripten-finalize: Emit illegal dynCalls, and legalize them (#…

version_65: Handle EM_ASM/EM_JS in LLVM wasm backend O0 output (#1888)

See emscripten-core/emscripten#7928 - we have been optimizing all wasms until now, and noticed this when the wasm object file path did not do so. When not optimizing, our methods of handling EM_ASM and EM_JS fail since the patterns are different.

Specifically, for EM_ASM we hunt for emscripten_asm_const(X, where X is a constant, but without opts it may be a get of a local. For EM_JS, the function body may not just contain a const, but a block with a set of the const and a return of a get later.

This adds logic to track gets and sets in basic blocks, which is sufficient to handle this.

1.38.25: More misc ASAN fixes (#1882)

* fix buffer overflow in simple_ast.h printing.
* check wasm binary format reading of function export indexes for errors.
* check if s-expr format imports have a non-empty module and base.

Fixes #1876
Fixes #1877
Fixes #1879