CSE Machine: clearing `CseMachine.masterLayout` undoes Fixed Layout and Central Alignment

[ThatLi]

When we allowed the CseMachine.masterLayout to be cleared through clearCse(), the layout completely lost the fixed properties, and the central alignment toggle fails completely. This effectively undoes the features added in our PR #3594.

Code excerpt:

function foo(n) {
    const msg = "This is frame " + stringify(n);
    const arr = list(1, 2, 3);
}

for (let i = 0; i < 3; i = i + 1) {
    foo(i);
}

With clearing layout in clearCse():

From the above images, the layout is no longer fixed.

This is when the alignment is toggled.

Without clearing layout in clearCse():

From the above images, this fixed frame behavior is the intended effect of our PR. (Ignore the detached arrow binding, this is currently expected)

This is what should have happened when the alignment is toggled. (Again, ignore the detached arrow binding, this is currently expected)