Reintroduce and fix modernize-use-equals-default clang-tidy check. (E…

…xawind#524)

.clang-tidy

@@ -1,5 +1,5 @@
 ---
-Checks:          'clang-diagnostic-*,clang-analyzer-*,corecppguidelines-*,modernize-*,readability-*,-readability-magic-numbers,-readability-identifier-naming,-modernize-avoid-c-arrays,-modernize-use-trailing-return-type,-readability-named-parameter,-readability-implicit-bool-conversion,-readability-isolate-declaration,-readability-braces-around-statements,-readability-inconsistent-declaration-parameter-name,-modernize-use-emplace,-readability-qualified-auto,-readability-static-accessed-through-instance,-readability-container-size-empty,-modernize-make-unique,-readability-make-member-function-const,-readability-uppercase-literal-suffix,-readability-convert-member-functions-to-static,-modernize-use-override,-readability-redundant-member-init,-modernize-use-bool-literals,-readability-const-return-type,-readability-avoid-const-params-in-decls,-modernize-pass-by-value,-modernize-loop-convert,-readability-else-after-return,-modernize-return-braced-init-list,-readability-simplify-boolean-expr,-modernize-use-equals-default,-clang-analyzer-optin.cplusplus.VirtualCall'
+Checks:          'clang-diagnostic-*,clang-analyzer-*,corecppguidelines-*,modernize-*,readability-*,-readability-magic-numbers,-readability-identifier-naming,-modernize-avoid-c-arrays,-modernize-use-trailing-return-type,-readability-named-parameter,-readability-implicit-bool-conversion,-readability-isolate-declaration,-readability-braces-around-statements,-readability-inconsistent-declaration-parameter-name,-modernize-use-emplace,-readability-qualified-auto,-readability-static-accessed-through-instance,-readability-container-size-empty,-modernize-make-unique,-readability-make-member-function-const,-readability-uppercase-literal-suffix,-readability-convert-member-functions-to-static,-modernize-use-override,-readability-redundant-member-init,-modernize-use-bool-literals,-readability-const-return-type,-readability-avoid-const-params-in-decls,-modernize-pass-by-value,-modernize-loop-convert,-readability-else-after-return,-modernize-return-braced-init-list,-readability-simplify-boolean-expr,-clang-analyzer-optin.cplusplus.VirtualCall'
 WarningsAsErrors: ''
 HeaderFilterRegex: '^((?!/amrex/Src/|/googletest/).)*$'
 AnalyzeTemporaryDtors: false

amr-wind/incflo.cpp

@@ -29,7 +29,7 @@ incflo::incflo()
     set_background_pressure();
 }
 
-incflo::~incflo() {}
+incflo::~incflo() = default;
 
 /** Initialize AMR mesh data structure.
  *