build: Reduce the verbosity of 'go test'

Otherwise, there's so much spew from 'go test', including the successful
tests, that the actual failures don't stand out.

Note that, the different steps involved in building the code base are a
lot more interdependent on each other.  Hence, some extra verbosity
can help understand what caused a build failure on non-interactive build
environments.  In contrast, the runtime outputs from each test case are
a lot more isolated and independent from one another.  The additional
verbosity from successful tests doesn't really help understand why a
particular test failed.

#1186

src/meson.build

@@ -72,4 +72,4 @@ endif
 
 test('go fmt', meson_go_fmt_program, args: [meson.current_source_dir()])
 test('go vet', go, args: ['vet', '-c', '3', './...'], workdir: meson.current_source_dir())
-test('go test', go, args: ['test', '-v', '-vet', 'off', './...'], workdir: meson.current_source_dir())
+test('go test', go, args: ['test', '-vet', 'off', './...'], workdir: meson.current_source_dir())