Join Consecutive Constant/Variable Declaration in Compile Result

[Alexius-Huang]

What?
We can join consecutive constant/variable declaration into a single line.

Why?
A way of minimize the compilation result.

For instance, the code below:

Num foo = 123
Num bar = foo + 456
Num baz = foo + 789 * bar

originally compiles into:

const foo = 123;
const bar = foo + 456;
const baz = foo + (789 * bar);

It can be minimize into:

const foo = 123, bar = foo + 456, baz = foo + (789 * bar);

How?
Introduce a new optimization option joinConsecutiveVarOrConstDeclaration, if the option is true, returns the minimize result.