Clang-tidy misc-redundant-expression warnings

Hi, Matthias!

I run Clang-tidy (version 9) misc-redundant-expression check over KLayout code:

src/db/unit_tests/dbDeepRegionTests.cc:173:31: warning: both sides of overloaded operator are equivalent [misc-redundant-expression]
src/db/unit_tests/dbDeepRegionTests.cc:180:29: warning: both sides of overloaded operator are equivalent [misc-redundant-expression]
src/db/unit_tests/dbDeepRegionTests.cc:306:29: warning: both sides of overloaded operator are equivalent [misc-redundant-expression]
src/db/unit_tests/dbDeepRegionTests.cc:359:29: warning: both sides of overloaded operator are equivalent [misc-redundant-expression]
src/plugins/streamers/pcb/lay_plugin/layGerberImportDialog.cc:964:77: warning: both sides of operator are equivalent [misc-redundant-expression]
src/tl/tl/tlGlobPattern.cc:551:7: warning: expression is redundant [misc-redundant-expression]
src/tl/tl/tlUri.cc:123:59: warning: 'true' and 'false' expressions are equivalent [misc-redundant-expression]
src/tl/tl/tlUri.cc:44:23: warning: logical expression is always true [misc-redundant-expression]

dbDeepRegionTests.cc warnings are by design, but other are reasonable.