Change release build flags to optimize for performance

[evanwashere]

improves perf of deno ops/core calls that are not i/o bound at the cost of release build time
haven't tested on other platforms but on macOS arm deno cli is ~900kb larger and denort is 1mb smaller

last change to opt-level #6907

[CLAassistant]

All committers have signed the CLA.

[bartlomieju]

Looks like this change makes CI run twice as long

[evanwashere]

benchmark results of this pr
benchmark results of f5c28c6

[ry]

Hi @evanwashere, thanks for the patch but we need more analysis than this - it appears to increase build time. This patch is done to improve performance, what measurements are improving? Previously we found no measurable improvement in our benchmark suite using -O3. Happy to reopen and discuss further if you want to get into it.