Upgrade CanvasKit emscripten to version 1.39.16.

Changes are largely mechanical.  Non-mechanical changes to support newer
versions of emscripten are enumerated below, in format ${EMSCRIPTEN_VERSION}:
${RELEVANT_CHANGE}.

- 1.39.9: TOTAL_MEMORY has been renamed INITIAL_MEMORY.
- 1.39.12: passing of linker flags to wasm-ld has changed in a way that requires
  supplying `--no-entry` to avoid error message "wasm-ld: error: entry symbol
  not defined (pass --no-entry to suppress): main".
- 1.39.16: The factory function created by using `MODULARIZE` build option now
  returns a Promise instead of the module instance.  As such, the ready.js
  workaround is removed.  Note this is a breaking API change for CanvasKit,
  which now uses just `then()` and not `ready().then()`.
- 1.38.33: `emsdk install` hasn't required the `-64bit` suffix on version names
  since `1.38.33`, so we remove them.  E.g. `emsdk install sdk-1.39.6-64bit`
  simply becomes `emsdk install sdk-1.39.16`.

cf. https://github.com/emscripten-core/emscripten/blob/master/ChangeLog.md

Bug: NONE
Change-Id: Iabec4bd5ad7db2e0715ad42c2e4cf7d67b192b4c
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/291182
Reviewed-by: Kevin Lubick <kjlubick@google.com>
34 files changed