option for wasm-validate to output context

Currently wasm-validate outputs the offending operation, however the context needs to be grep'ed manually:

wasm-validate  main.wasm   
main.wasm:000007b: error: type mismatch in i32.and, expected [i32, i32] but got [... i64, i32]

wasm-objdump main.wasm -d | grep -B3 7b
 000077: 20 03                      |   local.get 3 <width>
 000079: 53                         |   i64.lt_s
 00007a: 71                         |   i32.and
 00007b: 04 40                      |   if

It would be nice to have a flag for wasm-validate to directly output the context, maybe even smart enough to trace back all relevant preceding ops.

Start by reproducing the shown validation error with wasm-validate and compare its address with wasm-objdump -d output. Read the wasm-validate command path and establish the intended context or tracing scope with maintainers. Done means the selected flag produces useful surrounding operations for the example, with tests covering the chosen output.