Revert "[WebAssembly] MC layer writes table symbols to object files"

This reverts commit d8066186.
Review: https://reviews.llvm.org/D92215

We had issues where older versions of wasm-ld were crashing on object
files containing a table symbol.  We decided that the best strategy
going forward is to only generate these symbol if refernece types is
enabled.  Without reference types enabled we should never geneate a
table symbol or a TABLE_NUMBER relocation.

This revert is in addition to the one already reverted in
https://reviews.llvm.org/D95005.

The plan is to re-land these in updated form after the llvm 12 branch.

Differential Revision: https://reviews.llvm.org/D95420