This removes dead methods from wasm-compiler.h and wasm-compiler.cc.
Even though e.g. {BranchExpectTrue} could become useful again in the
future, we still have {BranchExpectFalse} as a template to easily add it
back, and for now it's just untested code which adds to the compile time
and maintenance cost.

R=manoskouk@chromium.org

Bug: v8:10949
Change-Id: Ia3918c4cdfedd2c56bfbfbe7173d11386b9f2499
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2544522Reviewed-by: Manos Koukoutos <manoskouk@chromium.org>
Commit-Queue: Clemens Backes <clemensb@chromium.org>
Cr-Commit-Position: refs/heads/master@{#71293}