After renaming the WasmExecutionMode constants, I should also have
renamed the tests generated from the WASM_EXEC_TEST macro. This CL
cleans this up.

R=titzer@chromium.org

Change-Id: Ifcb1a1e09422a06f89c3b44dc6b7799d3f84f7ac
Reviewed-on: https://chromium-review.googlesource.com/744044
Commit-Queue: Clemens Hammacher <clemensh@chromium.org>
Reviewed-by: Andreas Haas <ahaas@chromium.org>
Cr-Commit-Position: refs/heads/master@{#49082}