Significantly optimizes array builtin function calls. EDIT: and other lualib impovements

This depends on both runtime-benchmark and preceding-statements pull requests. If and when those get merged I'll rebase.

Implementation notes:

• For some cases this might break with preceding statements, will fix whenever preceding statements gets more finalized
• Optimizations have the most effect on lua5.3, minimal effect on luaJIT (as can be expected).
• Introduced NodeFlags concept (which absorbs existing FunctionExpressionFlags)
• Added lualib dependency exactness test, and fix detected bugs

General optimization methods:

• Append to array instead of array = array.concat(...)
• Use items[] instead of ...items[]. This allows optimizing cases such as array.push(...anotherArray), and also is slightly faster than vararg anyways (based on my local benchmarks). This does however create backwards incompatibilities
• #array is actually a O(lgN) operation; so length is stored/computed where possible
• all array indexes are replaced with lua indexes (used as arr[i-1], which gets translated to lua as arr[i]), avoiding an addition on every indexing. Based on my benchmarks, even if this happens only once in a simple loop, this gives a ~10% speedup
• All for loops (numeric and array iteration) are replaced with for(const i of $range(...)). This both helps in "storing" #array so it isn't recomputed, seems to be friendlier to the compiler (measurable speedup in some cases), and is faster than ipairs. I assume the potential behavior change (due to metatables) isn't an issue because lualib already wasn't consistent in using ipairs or numeric indexes
• Avoid Math.min/Math.max -- global variable access

Some particular methods:

• array.push(oneElement) is optimized to something like array[#array+1] = oneElement (+ changes for execution order). This is the most significant optimization
• array.join() is replaced with essentially an array.map + table.concat call -- lua string manipulation is very slow, and one table.concat call is much faster than many concats
• array.shift() is inlined (since array.pop() already is?)

Other:

• Normalized naming of variables
• Found and fixed a few corner-case bugs

Benchmarks running on my local machine, for lua5.3 (Note: I changed the benchmarks to run x5 times for more stable results):

runtime