meson: Use dicts for test definitions

Although this slightly more verbose it makes it much easier to reason
about. The code that produces the tests heavily benefits from this.

Test lists are also now sorted by test name.

src/boot/efi/meson.build

@@ -389,18 +389,26 @@ if efi_arch[1] in ['ia32', 'x86_64']
 endif
 
 tests += [
-        [files('test-efi-string.c', 'efi-string.c')],
+        {
+                'sources' : files(
+                        'test-efi-string.c',
+                        'efi-string.c',
+                )
+        },
 ]
 
 # BCD parser only makes sense on arches that Windows supports.
 if efi_arch[1] in ['ia32', 'x86_64', 'arm', 'aarch64']
         systemd_boot_sources += files('bcd.c')
         tests += [
-                [files('test-bcd.c', 'efi-string.c'),
-                 [],
-                 [libzstd],
-                 [],
-                 'HAVE_ZSTD'],
+                {
+                        'sources' : files(
+                                'test-bcd.c',
+                                'efi-string.c',
+                        ),
+                        'dependencies' : libzstd,
+                        'condition' : 'HAVE_ZSTD',
+                },
         ]
         fuzzers += [
                 [files('fuzz-bcd.c', 'bcd.c', 'efi-string.c')],