RegExp, TypedArrays, Proxy, Temporal and Intl in one day

A forked regress engine for regular expressions, eleven TypedArray constructors, Proxy traps, Temporal type by type, the whole Intl namespace, a mark-sweep GC, and a 17,400-line vm.rs split into a folder.

The busiest day in the log. 8520b6a8 wires regular expressions through the regress crate (later forked for UTF-16 execution and a regex JIT). 65e33aed: ArrayBuffer and eleven TypedArray constructors. 48633f27: Proxy traps. 4a3f85b6 through 00df2adc: Temporal, from Duration to PlainDate to Instant to Now. ebf7dca3: "implement the Intl namespace + all 11 services (0 -> ~340 tests)". a9b1d901: "split the 17.4k-line vm.rs into a vm/ module folder". b5d691e1: a mark-sweep collector for the new VM.