The lowering of {JSToBoolean} operators in {JSTypedLowering} inserts
loads that are not part of the effect chain. This does not play well
with effect-sensitive data flow analysis (e.g. escape analysis). This
removes the lowering in question, we can implement it using a dedicated
simplified operator eventually if needed.

R=bmeurer@chromium.org
TEST=mjsunit/wasm/embenchen/lua_binarytrees

Review-Url: https://codereview.chromium.org/2366363003
Cr-Commit-Position: refs/heads/master@{#39773}