Reproduction Steps:
1- Open the reproduction project using Unity 5.5. (860948_reproduction.zip)
2- Wait for import, Unity will ask to update scripts, accept it.
3- Wait for Script Updater to finish.

Expected Result: Unity updates all scripts and compiles them.
Actual Result: Too Many Heap Sections error pops up and compiling starts and fails again.

Fixed in: 5.6.5f1

Reproducible: 5.5.0p3 5.5.0a4

Not reproducible: 5.6.0b1, 5.5.0a3 5.4.3f1, 5.3.6f1

Regression introduced with: 5.5.0a4

When a project with a huge amount of scripts is opened in a newer version, script updater fails with an error message: "Too many heap sections".
The reproduction project has ~5000 scripts with ~200.000 errors.
Same project is successfully converted when the amount of scripts is reduced to 1500 and the amount of errors is reduced proportionally.