[WebAssembly] Support Emscripten EH/SjLj in Wasm64

In wasm64, the signatures of some library functions and global variables
defined in Emscripten change:
- `emscripten_longjmp`: `(i32, i32) -> ()` -> `(i64, i32) -> ()`
  This changes because the first argument is the address of a memory
  buffer. This in turn causes more changes below.
- `setThrew`: `(i32, i32) -> ()` -> `(i64, i32) -> ()`
  `emscripten_longjmp` calls `setThrew` with the i64 buffer argument as
  the first parameter.
- `__THREW__` (global var): `i32` to `i64`
  `setThrew`'s first argument is set to this `__THREW__` variable, so it
  should change to i64 as well.
- `testSetjmp`: `(i32, i32*, i32) -> (i32)` -> `(i64, i32*, i32) -> (i32)`
  In the code transformation done in this pass, the value of `__THREW__`
  is passed as the first parameter of `testSetjmp`.

This patch creates some helper functions to easily get types that become
different depending on the wasm32/wasm64, and uses them to change
various function signatures and code transformations. Also updates the
tests with WASM32/WASM64 check lines.

(Untested) Emscripten side patch: https://github.com/emscripten-core/emscripten/pull/14108

Reviewed By: aardappel

Differential Revision: https://reviews.llvm.org/D101985