Removing static compile method; use runtime instances instead

[Casuso]

No description provided.

[cetra3]

Hey thanks for the PR!

I feel like this would change the ergonomics of the library a little bit & interested to see the context/reason behind this change?

[khandar-william]

Could be related, I got the following compile error while using SP1 zkVM where the guest code contains jmespath

error[E0277]: `(dyn functions::Function + 'static)` cannot be sent between threads safely
   --> /home/builder/.cargo/registry/src/index.crates.io-6f17d22bba15001f/jmespath-0.3.0/src/lib.rs:124:1
    |
124 | / lazy_static! {
125 | |     pub static ref DEFAULT_RUNTIME: Runtime = {
126 | |         let mut runtime = Runtime::new();
127 | |         runtime.register_builtin_functions();
128 | |         runtime
129 | |     };
130 | | }
    | |_^ `(dyn functions::Function + 'static)` cannot be sent between threads safely
    |
    = help: the trait `Send` is not implemented for `(dyn functions::Function + 'static)`, which is required by `Lazy<Runtime>: Sync`
    = note: required for `Unique<(dyn functions::Function + 'static)>` to implement `Send`
note: required because it appears within the type `Box<(dyn functions::Function + 'static)>`
   --> /rustc/129f3b9964af4d4a709d1383930ade12dfe7c081/library/alloc/src/boxed.rs:196:12
    = note: required because it appears within the type `(std::string::String, Box<(dyn functions::Function + 'static)>)`
    = note: required for `hashbrown::raw::RawTable<(std::string::String, Box<(dyn functions::Function + 'static)>)>` to implement `Send`
note: required because it appears within the type `hashbrown::map::HashMap<std::string::String, Box<(dyn functions::Function + 'static)>, RandomState>`
   --> /rust/deps/hashbrown-0.14.3/src/map.rs:190:12
note: required because it appears within the type `HashMap<std::string::String, Box<(dyn functions::Function + 'static)>>`
   --> /rustc/129f3b9964af4d4a709d1383930ade12dfe7c081/library/std/src/collections/hash/map.rs:213:12
note: required because it appears within the type `Runtime`
   --> /home/builder/.cargo/registry/src/index.crates.io-6f17d22bba15001f/jmespath-0.3.0/src/runtime.rs:13:12
    |
13  | pub struct Runtime {
    |            ^^^^^^^
    = note: required for `spin::once::Once<Runtime>` to implement `Sync`
note: required because it appears within the type `Lazy<Runtime>`
   --> /home/builder/.cargo/registry/src/index.crates.io-6f17d22bba15001f/lazy_static-1.5.0/src/core_lazy.rs:12:12
    |
12  | pub struct Lazy<T: Sync>(Once<T>);
    |            ^^^^
    = note: shared static variables must have a type that implements `Sync`
    = note: this error originates in the macro `__lazy_static_create` which comes from the expansion of the macro `lazy_static` (in Nightly builds, run with -Z macro-backtrace for more info)

By removing the static DEFAULT_RUNTIME, I assume this error would disappear