Remove deprecated emcc flags, and update emsdk to 2.1.44.

Because emsdk updated the necessary version of build_bazel_rules_nodejs
from 4.4.1 to 5.8, we needed to modify the karma_test rule
to account for the updated generated rules of npm packages.
This was most cleanly handled by making a karma_with_plugins
target to use instead of the stock @npm//karma/bin:karma

Bug: https://g-issues.skia.org/issues/40045352
Bug: https://g-issues.skia.org/issues/40045353
Change-Id: I96a9b0b700aa3ecfac51662768efc07facd5edd3
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/738156
Reviewed-by: Leandro Lovisolo <lovisolo@google.com>
Owners-Override: Kevin Lubick <kjlubick@google.com>
15 files changed