[Compiler] Bug fixes

[water111]

• Split method into method-of-type and method-of-object to avoid ambiguity [Compiler] Split method operator into method-of-type and method-of-object #225
• Fixed (-> <obj-of-type-array> type) not working [Compiler] Access type field of an array doesn't work #224
• Fixed use-after free [Compiler] Use-after-free when tests fail #222

[coveralls]

Pull Request Test Coverage Report for Build 534367137

• 15 of 17 (88.24%) changed or added relevant lines in 5 files are covered.
• 3 unchanged lines in 2 files lost coverage.
• Overall coverage decreased (-0.003%) to 67.195%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
goalc/compiler/compilation/Type.cpp	7	9	77.78%

Files with Coverage Reduction	New Missed Lines	%
goalc/compiler/compilation/Type.cpp	1	89.21%
common/type_system/TypeSystem.cpp	2	72.97%

Totals
Change from base Build 534020348:	-0.003%
Covered Lines:	26978
Relevant Lines:	40149

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💛 - Coveralls