Tidy up the output for memset and memcpy, and add a test.
Don't emit JS declarations for LLVM intrinsics expanded inline.
Don't emit redirects for llvm.memcpy.p0i8.p0i8.i32 and friends.

We never reference these intrinsics by name, so we don't need redirects
for them.
Disable the LowerExpectIntrinsic pass.