Fix memory operations (#101)

* fix: symbol name for combined z3 model

* compute composed model by z3::model directly

* move antlr interp files to .antlr folder so we can debug them in vscode

* fix load syntax

* support all memory operations

* a note

* remove a print in test

Author: butterunderflow

benchmarks/wasm/long_loop.wat

@@ -16,7 +16,7 @@
       i32.add
       local.set 1
       local.get 0
-      call 0
+      drop
       local.get 0
       i32.const 100000
       i32.lt_s