eliminate v8_enable_pointer_compression setting patch in favor of using v8_disable_pointer_compression Starlark transition

[mpwarres]

proxy-wasm-cpp-host currently patches V8's definition of the v8_enable_pointer_compression setting here in order to disable V8 pointer compression.

V8 also provides a Starlark transition to support building with pointer compression disabled here, which proxy-wasm-cpp-host appears to allowlist use of here, but AFAICT proxy-wasm-cpp-host build rules do not actually make use of it.

(Sidenote: the original reason for disabling pointer compression is documented in #242 and https://issues.chromium.org/issues/42202536: "New pointer compression features severely limit the maximum number of WasmVMs that can be created in a single process, so disable it".)

If possible, we should switch proxy-wasm-cpp-host build rules to use the transition, which would avoid the need to patch the setting definition.