8026161: Don't narrow floating-point literals in the lexer
Reviewed-by: hannesw, jlaskey
<test/script/basic/JDK-8012164.js>.error(test/script/basic/JDK-8012164.js:38)
<test/script/basic/JDK-8012164.js>.func(test/script/basic/JDK-8012164.js:33)
<test/script/basic/JDK-8012164.js>.<program>(test/script/basic/JDK-8012164.js:47)