ffi: fix FLOAT_32 and FLOAT_64 type constants

[watilde]

Test code

$ cat test.js
const ffi = require('node:ffi');

const { functions } = ffi.dlopen('libm.so.6', {
  sinf: { parameters: [ffi.types.FLOAT_32], result: ffi.types.FLOAT_32 },
});

console.log(functions.sinf(1.0));

Before

$ ./node --experimental-ffi test.js
node:ffi:75
    throw error;
    ^

TypeError: Unsupported FFI type: float32
    at Object.dlopen (node:ffi:71:91)
    at Object.<anonymous> (/home/moku/Developments/watilde/node/test.js:3:27)
    at Module._compile (node:internal/modules/cjs/loader:1829:14)
    at Object..js (node:internal/modules/cjs/loader:1969:10)
    at Module.load (node:internal/modules/cjs/loader:1552:32)
    at Module._load (node:internal/modules/cjs/loader:1354:12)
    at wrapModuleLoad (node:internal/modules/cjs/loader:255:19)
    at Module.executeUserEntryPoint [as runMain] (node:internal/modules/run_main:154:5)
    at node:internal/main/run_main_module:33:47 {
  code: 'ERR_INVALID_ARG_VALUE'
}

Node.js v26.0.0-pre

After

$ ./node --experimental-ffi test.js
0.8414709568023682
(node:721215) ExperimentalWarning: FFI is an experimental feature and might change at any time
(Use `node --trace-warnings ...` to show where the warning was created)

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 89.63%. Comparing base (3a53447) to head (843d824).
⚠️ Report is 5 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #62892      +/-   ##
==========================================
+ Coverage   89.60%   89.63%   +0.02%     
==========================================
  Files         706      706              
  Lines      219179   219179              
  Branches    41993    41998       +5     
==========================================
+ Hits       196400   196452      +52     
+ Misses      14675    14627      -48     
+ Partials     8104     8100       -4     

Files with missing lines	Coverage Δ
lib/ffi.js	96.56% <100.00%> (ø)

... and 33 files with indirect coverage changes

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