Upgrade EVMC to version 6.0.0

[chfast]

No description provided.

[axic]

Rebased.

[axic]

@hugo-dc some new issue:

/home/builder/project/test/tools/libtesteth/TestSuite.cpp(157): fatal error: in "GeneralStateTests/stEWASMTests": Compiled test folder contains test without Filler: callData.json

[hugo-dc]

@axic the fillers are removed here in this same PR:

hera/circle.yml

Lines 129 to 130 in 8e5a263

	# Remove test fillers because testeth will try to compare hashes of files.
	rm tests/src -r

[axic]

Two failures:

[2018-11-01 23:11:46.834357] [0x00007f3825666800] [info]    Failed to set EVMC parameter 'engine'
[2018-11-01 23:11:46.834389] [0x00007f3825666800] [info]    Loaded EVMC module: hera 0.1.0-5+commit.a5207b71 (/home/builder/build/src/libhera.so)

testeth 1.5.0-alpha.4
[2018-11-01 23:12:12.958957] [0x00007f67175f6140] [info]    Failed to set EVMC parameter 'evm1mode'
[2018-11-01 23:12:12.958990] [0x00007f67175f6140] [info]    Loaded EVMC module: hera 0.1.0-5+commit.a5207b71 (/home/builder/build/src/libhera.so)
Running tests using path: "tests"
Running 1 test case...
/home/builder/project/test/tools/libtesteth/TestSuite.cpp(124): error: in "GeneralStateTests/stExample": Test tests/GeneralStateTests/stExample/add11.json in add11 is outdated. Filler hash is different! ( '6a4e' != '4cba') 
Test Case "stExample": 
100%

*** 1 failure is detected (5 failures are expected) in the test module "Master Test Suite"
Exited with code 200

[codecov-io]

Codecov Report

Merging #443 into master will decrease coverage by 0.53%.
The diff coverage is 55.26%.

@@            Coverage Diff             @@
##           master     #443      +/-   ##
==========================================
- Coverage   69.82%   69.29%   -0.54%     
==========================================
  Files           8        8              
  Lines        1097     1104       +7     
  Branches      136      137       +1     
==========================================
- Hits          766      765       -1     
- Misses        300      308       +8     
  Partials       31       31

[chfast]

These were just warnings, not failures. They are fixed now.
Anyway, testeth still complains about fillers mismatch.

[axic]

Depends on ewasm/tests#103