This CL adds a new header src/debug/interface-types.h, moves the
definition of Location from the debug-interface.h to this new header,
and adds a new definition for the WasmDisassembly types.
This allows to use the types in other implementation files or headers
without having to include the entire debug-interface.h, reducing build
dependencies and compile time (especially for incremental builds).

The WasmDisassembly type replaces the old
std::pair<std::string, std::vector<std::tuple<...>>>, which was a bit
hard to unravel.

R=yangguo@chromium.org, kozyatinskiy@chromium.org, titzer@chromium.org

Review-Url: https://codereview.chromium.org/2529383002
Cr-Commit-Position: refs/heads/master@{#41488}