Bug 1875017 - Skip laziness validation test on ccov build. r=bthrall

Differential Revision: https://phabricator.services.mozilla.com/D198789

js/src/jit-test/tests/parser/stencil-laziness-validate.js

@@ -1,3 +1,5 @@
+// |jit-test| skip-if: isLcovEnabled()
+
 load(libdir + "asserts.js");
 
 const gWithSource = newGlobal({discardSource: false});