[ntuple] Fix kReal32Quant decoding for 32-bit values

[undefined-panda]

Avoid 5-bit masking of JS shift counts, which made divisor 0 at nbits = 32.
Cast res to Uint32, s.t. bit 31 is not interpreted as sign bit.

[linev]

Can you provide small test file with such corner cases - from this and previous PR.
And node.js macro which checks expected content.
Like in demo/node/rntuple_test.js

I want to include this macro in jsroot-ci.yml

[undefined-panda]

real32quant.zip
This folder contains a .root and .mjs file from the RNTuple Validation Suite, aswell as the JSON files created by ROOT, JSROOT before the change and after. It can be seen, that (with my current floatToHex function) the JSROOT result is more precise than ROOT, since JS works with double while ROOT works with floats for quant. floats. I hope these files are self-explanatory, but if not, please let me know.

[linev]

You are using #jsroot_reader module. I guess, it is some private module from you.

Can you adjust reader.mjs that it works without it and instead writing some JSON file compare read values with some predefined values. Something like code from rntuple_test,js:

   for (const field of fields) {
      try {
         const value = this.tgtobj[field],
               expected = expectedValues[field];

         if (!compare(expected, value, epsilonValues[field])) {
            console.error(`FAILURE: ${field} at entry ${entryIndex} expected ${JSON.stringify(expected)}, got ${JSON.stringify(value)}`);
            any_error = true;
         } else {
            const res = typeof value === 'bigint' ? value.toString() + 'n' : JSON.stringify(value);
            console.log(`OK: ${field} at entry ${entryIndex} = ${res}`);
         }
      } catch (err) {
         console.error(`ERROR: Failed to read ${field} at entry ${entryIndex}: ${err.message}`);
         any_error = true;
      }
   }