Bug 910796 - SpiderMonkey: Micro-optimize clampIntToUint8. r=mjrosenb
Backed out 10 changesets (bug 914944, bug 871445) for mochitest failures on a CLOSED TREE.

Backed out changeset a840638b5b18 (bug 914944)
Backed out changeset f40c7d5790bd (bug 914944)
Backed out changeset e1b288e29663 (bug 871445)
Backed out changeset 6242ddf7b6c7 (bug 871445)
Backed out changeset 7679185a8cf3 (bug 871445)
Backed out changeset 639ec7a627f8 (bug 871445)
Backed out changeset 93b050a79db4 (bug 871445)
Backed out changeset ec3382ceef99 (bug 871445)
Backed out changeset 51c0d5230306 (bug 871445)
Backed out changeset 76c9069bdb56 (bug 871445)