Updating provider_cldr and testdata to CLDR 38.1.0-BETA4

[sffc]

Fixes #409
Depends on #407

I implemented a downloader for the new all-in-one CLDR JSON distribution. I can't switch the testdata over to CLDR 38, though, until we support the "e" operand. Right now I get the error:

thread 'main' panicked at 'Rule parsing failed.: ExpectedOperand', components/provider_cldr/src/transform/plurals.rs:141:47

[codecov-io]

Codecov Report

Merging #441 (8f1bda3) into master (2a9adbc) will decrease coverage by 0.02%.
The diff coverage is 12.50%.

@@            Coverage Diff             @@
##           master     #441      +/-   ##
==========================================
- Coverage   74.92%   74.90%   -0.03%     
==========================================
  Files          90       90              
  Lines        4662     4658       -4     
==========================================
- Hits         3493     3489       -4     
  Misses       1169     1169              

Impacted Files	Coverage Δ
...omponents/provider_fs/src/bin/icu4x-cldr-export.rs	0.87% <0.00%> (ø)
...onents/provider_cldr/src/download/cldr_allinone.rs	27.27% <11.11%> (ø)
components/provider_cldr/src/download/io_util.rs	40.00% <16.66%> (-2.19%)	⬇️

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[coveralls]

Pull Request Test Coverage Report for Build 53fea1f91066148e0f3d6ebef8461124f0a86557-PR-441

• 2 of 20 (10.0%) changed or added relevant lines in 4 files are covered.
• 2 unchanged lines in 1 file lost coverage.
• Overall coverage decreased (-0.05%) to 74.06%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
components/provider_fs/src/bin/icu4x-cldr-export.rs	0	1	0.0%
resources/testdata/src/bin/icu4x-gen-testdata.rs	0	4	0.0%
components/provider_cldr/src/download/io_util.rs	1	6	16.67%
components/provider_cldr/src/download/cldr_allinone.rs	1	9	11.11%

Files with Coverage Reduction	New Missed Lines	%
resources/testdata/src/bin/icu4x-gen-testdata.rs	2	1.47%

Totals
Change from base Build 2a9adbca47e13371a314f5d98d0a48f3a2407916:	-0.05%
Covered Lines:	3603
Relevant Lines:	4865

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💛 - Coveralls

[srl295]

LGTM

[dpulls]

🎉 All dependencies have been resolved !

[zbraniecki]

lgtm!