POC: experimental --global flag.

[i4ki]

What this PR does / why we need it:

PoC of --global flag.

Which issue(s) this PR fixes:

none

Special notes for your reviewer:

Does this PR introduce a user-facing change?

yes

[github-actions]

metric: time/op
CloudReadLines-4: old 982µs ± 5%: new 1017µs ± 2%: delta: 3.63%
CloudReadLine-4: old 6.91ms ± 1%: new 7.01ms ± 1%: delta: 1.42%
ListFiles-4: old 52.9µs ± 1%: new 53.0µs ± 1%: delta: 0.00%
Generate-4: old 2.52s ± 2%: new 2.52s ± 1%: delta: 0.00%
GenerateRegex-4: old 1.73s ± 2%: new 1.72s ± 2%: delta: 0.00%
TokensForExpressionComplex-4: old 1.27ms ± 0%: new 1.26ms ± 0%: delta: -0.60%
TokensForExpressionPlainStringNoNewline-4: old 892ns ± 1%: new 890ns ± 1%: delta: -0.18%
TokensForExpressionStringWith100Newlines-4: old 22.4µs ± 1%: new 22.3µs ± 0%: delta: -0.44%
TokensForExpressionObjectWith100KeysWithNumberValues-4: old 1.46ms ± 1%: new 1.45ms ± 0%: delta: -0.38%
TokensForExpression-4: old 1.26ms ± 0%: new 1.26ms ± 0%: delta: 0.00%
PartialEvalComplex-4: old 431µs ± 0%: new 432µs ± 1%: delta: 0.28%
PartialEvalSmallString-4: old 3.66µs ± 1%: new 3.68µs ± 1%: delta: 0.45%
PartialEvalHugeString-4: old 1.85ms ± 0%: new 1.85ms ± 0%: delta: -0.12%
PartialEvalHugeInterpolatedString-4: old 4.90ms ± 1%: new 4.91ms ± 1%: delta: 0.00%
PartialEvalObject-4: old 21.6µs ± 1%: new 21.6µs ± 0%: delta: 0.00%
TmAllTrueLiteralList-4: old 6.27ms ± 0%: new 6.26ms ± 0%: delta: -0.15%
TmAllTrueFuncall-4: old 160µs ± 0%: new 160µs ± 0%: delta: -0.17%
TmAnyTrueLiteralList-4: old 147ms ± 0%: new 147ms ± 0%: delta: 0.00%
TmAnyTrueFuncall-4: old 160µs ± 0%: new 160µs ± 0%: delta: 0.00%
TmTernary-4: old 2.84µs ± 1%: new 2.85µs ± 0%: delta: 0.37%
TmTry-4: old 51.8µs ± 0%: new 51.8µs ± 0%: delta: 0.00%
metric: alloc/op
CloudReadLines-4: old 3.12MB ± 0%: new 3.12MB ± 0%: delta: 0.00%
CloudReadLine-4: old 3.37MB ± 0%: new 3.37MB ± 0%: delta: 0.00%
ListFiles-4: old 22.0kB ± 0%: new 22.0kB ± 0%: delta: 0.01%
Generate-4: old 2.32GB ± 0%: new 2.32GB ± 0%: delta: 0.00%
GenerateRegex-4: old 956MB ± 0%: new 956MB ± 0%: delta: 0.00%
TokensForExpressionComplex-4: old 412kB ± 0%: new 412kB ± 0%: delta: -0.00%
TokensForExpressionPlainStringNoNewline-4: old 592B ± 0%: new 592B ± 0%: delta: 0.00%
TokensForExpressionStringWith100Newlines-4: old 12.4kB ± 0%: new 12.4kB ± 0%: delta: 0.00%
TokensForExpressionObjectWith100KeysWithNumberValues-4: old 402kB ± 0%: new 402kB ± 0%: delta: -0.00%
TokensForExpression-4: old 412kB ± 0%: new 412kB ± 0%: delta: 0.00%
PartialEvalComplex-4: old 353kB ± 0%: new 353kB ± 0%: delta: 0.00%
PartialEvalSmallString-4: old 1.74kB ± 0%: new 1.74kB ± 0%: delta: 0.00%
PartialEvalHugeString-4: old 166kB ± 0%: new 166kB ± 0%: delta: 0.00%
PartialEvalHugeInterpolatedString-4: old 4.38MB ± 0%: new 4.38MB ± 0%: delta: 0.00%
PartialEvalObject-4: old 20.4kB ± 0%: new 20.4kB ± 0%: delta: 0.00%
TmAllTrueLiteralList-4: old 1.74MB ± 0%: new 1.74MB ± 0%: delta: 0.00%
TmAllTrueFuncall-4: old 45.5kB ± 0%: new 45.5kB ± 0%: delta: 0.00%
TmAnyTrueLiteralList-4: old 37.9MB ± 0%: new 37.9MB ± 0%: delta: 0.00%
TmAnyTrueFuncall-4: old 45.6kB ± 0%: new 45.6kB ± 0%: delta: 0.00%
TmTernary-4: old 1.20kB ± 0%: new 1.20kB ± 0%: delta: 0.00%
TmTry-4: old 11.2kB ± 0%: new 11.2kB ± 0%: delta: 0.00%
metric: allocs/op
CloudReadLines-4: old 5.54k ± 0%: new 5.54k ± 0%: delta: 0.00%
CloudReadLine-4: old 60.0k ± 0%: new 60.0k ± 0%: delta: 0.00%
ListFiles-4: old 321 ± 0%: new 321 ± 0%: delta: 0.00%
Generate-4: old 25.9M ± 0%: new 25.9M ± 0%: delta: 0.00%
GenerateRegex-4: old 18.6M ± 0%: new 18.6M ± 0%: delta: 0.00%
TokensForExpressionComplex-4: old 4.93k ± 0%: new 4.93k ± 0%: delta: 0.00%
TokensForExpressionPlainStringNoNewline-4: old 21.0 ± 0%: new 21.0 ± 0%: delta: 0.00%
TokensForExpressionStringWith100Newlines-4: old 228 ± 0%: new 228 ± 0%: delta: 0.00%
TokensForExpressionObjectWith100KeysWithNumberValues-4: old 3.29k ± 0%: new 3.29k ± 0%: delta: 0.00%
TokensForExpression-4: old 4.93k ± 0%: new 4.93k ± 0%: delta: 0.00%
PartialEvalComplex-4: old 2.83k ± 0%: new 2.83k ± 0%: delta: 0.00%
PartialEvalSmallString-4: old 23.0 ± 0%: new 23.0 ± 0%: delta: 0.00%
PartialEvalHugeString-4: old 35.0 ± 0%: new 35.0 ± 0%: delta: 0.00%
PartialEvalHugeInterpolatedString-4: old 23.1k ± 0%: new 23.1k ± 0%: delta: 0.00%
PartialEvalObject-4: old 125 ± 0%: new 125 ± 0%: delta: 0.00%
TmAllTrueLiteralList-4: old 13.6k ± 0%: new 13.6k ± 0%: delta: 0.00%
TmAllTrueFuncall-4: old 460 ± 0%: new 460 ± 0%: delta: 0.00%
TmAnyTrueLiteralList-4: old 252k ± 0%: new 252k ± 0%: delta: 0.00%
TmAnyTrueFuncall-4: old 462 ± 0%: new 462 ± 0%: delta: 0.00%
TmTernary-4: old 28.0 ± 0%: new 28.0 ± 0%: delta: 0.00%
TmTry-4: old 146 ± 0%: new 146 ± 0%: delta: 0.00%