This commit adds support for specifying --max-old-space-size as a
percentage of system memory, in addition to the existing MB format.
A new HandleMaxOldSpaceSizePercentage method parses percentage values,
validates that they are within the 0-100% range, and provides clear
error messages for invalid input. The heap size is now calculated
based on available system memory when a percentage is used.

Test coverage has been added for both valid and invalid cases.
Documentation and the JSON schema for CLI options have been updated
with examples for both formats.

Refs: #57447
PR-URL: #59082
Backport-PR-URL: #59631
Reviewed-By: Chengzhong Wu <legendecas@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Moshe Atlow <moshe@atlow.co.il>
Reviewed-By: theanarkh <theratliter@gmail.com>
Reviewed-By: Daeyeon Jeong <daeyeon.dev@gmail.com>

Add validation to ensure that --max-old-space-size-percentage cannot
be used when available memory cannot be calculated, preventing
undefined behavior when memory detection fails.

Also enhance test-process-constrained-memory.js to support testing
in constrained environments where memory calculation may fail.

PR-URL: #59460
Backport-PR-URL: #59631
Reviewed-By: theanarkh <theratliter@gmail.com>
Reviewed-By: Moshe Atlow <moshe@atlow.co.il>

PR-URL: #60144
Backport-PR-URL: #59631
Reviewed-By: Richard Lau <richard.lau@ibm.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: Ulises Gascón <ulisesgascongonzalez@gmail.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>