BREAKING(ffi/unstable): always return u64 as bigint (#23981)

The mixed `number | bigint` representation was useful optimization for
pointers. Now, pointers are represented as V8 externals. As part of the
FFI stabilization effort we want to make `bigint` the only
representation for `u64` and `i64`.

BigInt representation performance is almost on par with mixed
representation with the added benefit that its less confusing and users
don't need manual checks and conversions for doing operations on the
value.

```
cpu: AMD Ryzen 5 7530U with Radeon Graphics
runtime: deno 1.43.6+92a8d09 (x86_64-unknown-linux-gnu)

file:///home/divy/gh/ffi/main.ts
benchmark                 time (avg)        iter/s             (min … max)       p75       p99      p995
-------------------------------------------------------------------------- -----------------------------
nop                        4.01 ns/iter 249,533,690.5     (3.97 ns … 10.8 ns) 3.97 ns 4.36 ns 9.03 ns
ret bigint                 7.74 ns/iter 129,127,186.8    (7.72 ns … 10.46 ns) 7.72 ns 8.11 ns 8.82 ns
ret i32                    7.81 ns/iter 128,087,100.5    (7.77 ns … 12.72 ns) 7.78 ns 8.57 ns 9.75 ns
ret bigint (add op)       15.02 ns/iter  66,588,253.2   (14.64 ns … 24.99 ns) 14.76 ns 19.13 ns 19.44 ns
ret i32    (add op)       12.02 ns/iter  83,209,131.8   (11.95 ns … 18.18 ns) 11.98 ns 13.11 ns 14.5 ns
```

1 files changed, 7 insertions, 25 deletions

diff --git a/ext/ffi/static.rs b/ext/ffi/static.rs
index 3920d885e..f08605754 100644
--- a/ext/ffi/static.rs
+++ b/ext/ffi/static.rs
@@ -2,8 +2,6 @@
 
 use crate::dlfcn::DynamicLibraryResource;
 use crate::symbol::NativeType;
-use crate::MAX_SAFE_INTEGER;
-use crate::MIN_SAFE_INTEGER;
 use deno_core::error::type_error;
 use deno_core::error::AnyError;
 use deno_core::op2;
@@ -90,45 +88,29 @@ pub fn op_ffi_get_static<'scope>(
     NativeType::U64 => {
       // SAFETY: ptr is user provided
       let result = unsafe { ptr::read_unaligned(data_ptr as *const u64) };
-      let integer: v8::Local<v8::Value> = if result > MAX_SAFE_INTEGER as u64 {
-        v8::BigInt::new_from_u64(scope, result).into()
-      } else {
-        v8::Number::new(scope, result as f64).into()
-      };
+      let integer: v8::Local<v8::Value> =
+        v8::BigInt::new_from_u64(scope, result).into();
       integer
     }
     NativeType::I64 => {
       // SAFETY: ptr is user provided
       let result = unsafe { ptr::read_unaligned(data_ptr as *const i64) };
-      let integer: v8::Local<v8::Value> = if result > MAX_SAFE_INTEGER as i64
-        || result < MIN_SAFE_INTEGER as i64
-      {
-        v8::BigInt::new_from_i64(scope, result).into()
-      } else {
-        v8::Number::new(scope, result as f64).into()
-      };
+      let integer: v8::Local<v8::Value> =
+        v8::BigInt::new_from_i64(scope, result).into();
       integer
     }
     NativeType::USize => {
       // SAFETY: ptr is user provided
       let result = unsafe { ptr::read_unaligned(data_ptr as *const usize) };
-      let integer: v8::Local<v8::Value> = if result > MAX_SAFE_INTEGER as usize
-      {
-        v8::BigInt::new_from_u64(scope, result as u64).into()
-      } else {
-        v8::Number::new(scope, result as f64).into()
-      };
+      let integer: v8::Local<v8::Value> =
+        v8::BigInt::new_from_u64(scope, result as u64).into();
       integer
     }
     NativeType::ISize => {
       // SAFETY: ptr is user provided
       let result = unsafe { ptr::read_unaligned(data_ptr as *const isize) };
       let integer: v8::Local<v8::Value> =
-        if !(MIN_SAFE_INTEGER..=MAX_SAFE_INTEGER).contains(&result) {
-          v8::BigInt::new_from_i64(scope, result as i64).into()
-        } else {
-          v8::Number::new(scope, result as f64).into()
-        };
+        v8::BigInt::new_from_i64(scope, result as i64).into();
       integer
     }
     NativeType::F32 => {