[turbofan] Emit constant pool before blocking it in AssembleArchTableSwitch.
[turbofan] Emit constant pool before blocking it in AssembleArchTableSwitch.

BUG=chromium:468749
LOG=NO
TEST=Emscripten/NBodyJava

Review URL: https://codereview.chromium.org/1014093005

Cr-Commit-Position: 972c6d2dc6dd5efdad1377c0d224e03eb8f276f7@{#27322}

UniversalFuture/moosh,UniversalFuture/moosh,UniversalFuture/moosh,UniversalFuture/moosh