improve tonumber/0 performance by parsing input as number literal

Previously, the tonumber/0 filter parses the input as JSON values, but
this is less-performant on large non-number strings. Parsing the input
string as number literal fixes the performance issue. Also, this fix
changes the filter to reject numbers with white spaces.

tests/jq.test

@@ -2000,8 +2000,8 @@ null
 2
 
 .[] |= try tonumber
-["1", "2a", "3", 4]
-[1, 3, 4]
+["1", "2a", "3", " 4 ", "5.67", ".89", "-876", "+5.43", 21]
+[1, 3, 5.67, 0.89, -876, 5.43, 21]
 
 # Also 1859, but from 2073
 any(keys[]|tostring?;true)