Use known-good locale when doing jflex codegen

jflex appears to be using the default locale for a String.toUpperCase
somewhere, which causes incorrect java code to be generated in the
turkish locale.

smali/build.gradle

@@ -128,6 +128,7 @@ task generateJflexSource(type: JavaExec) {
     args '-q'
     args '-d', relativePath("${jflexOutput}/org/jf/smali")
     args grammars.files.join(' ')
+    environment LC_ALL: "en_US"
 }
 
 compileJava.dependsOn generateParserAntlrSource, generateTreeWalkerAntlrSource, generateJflexSource