[move-unit-test] Fix move unit test cost table bug.

[jolestar]

ensure native cost table len equals native functions len, fix

move unit-test src unittest -f test_verify_sig
Running Move unit tests
thread '<unnamed>' panicked at 'index out of bounds: the len is 21 but the index is 22', /Users/badu/.cargo/git/checkouts/diem-5aa6d6b8b0487904/5a8ea73/language/move-core/types/src/gas_schedule.rs:251:10
stack backtrace:
   0:        0x1017768c4 - std::backtrace_rs::backtrace::libunwind::trace::hd9b9204470182ffc
                               at /rustc/c8dfcfe046a7680554bf4eb612bad840e7631c4b/library/std/src/../../backtrace/src/backtrace/libunwind.rs:90:5

diem update: starcoinorg/diem#210

[codecov]

Codecov Report

Merging #3030 (24aec7f) into master (7c1328f) will decrease coverage by 0.50%.
The diff coverage is 80.00%.

@@            Coverage Diff             @@
##           master    #3030      +/-   ##
==========================================
- Coverage   33.48%   32.99%   -0.49%     
==========================================
  Files         516      516              
  Lines       45959    45960       +1     
  Branches    20978    20966      -12     
==========================================
- Hits        15386    15161     -225     
- Misses      16311    16313       +2     
- Partials    14262    14486     +224     

Flag	Coverage Δ
unittests	32.99% <80.00%> (-0.49%)	⬇️

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
vm/natives/src/lib.rs	50.00% <ø> (ø)
vm/vm-runtime/src/starcoin_vm.rs	33.94% <80.00%> (-8.28%)	⬇️
...m/types/src/account_config/events/config_change.rs	66.67% <0.00%> (-33.33%)	⬇️
executor/src/block_executor.rs	22.23% <0.00%> (-20.00%)	⬇️
vm/natives/src/token.rs	22.23% <0.00%> (-13.33%)	⬇️
vm/natives/src/account.rs	18.75% <0.00%> (-12.50%)	⬇️
vm/vm-runtime/src/natives.rs	77.78% <0.00%> (-11.11%)	⬇️
commons/forkable-jellyfish-merkle/src/lib.rs	41.61% <0.00%> (-11.06%)	⬇️
chain/open-block/src/lib.rs	30.52% <0.00%> (-11.03%)	⬇️
vm/types/src/on_chain_config/mod.rs	42.47% <0.00%> (-10.95%)	⬇️
... and 68 more

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