Out-of-range wide constant indices: don't truncate to 64 bits

In tools that evaluate HDL select expressions (waveform derivation, linters, equivalence checkers), parsing a constant index into a 64-bit integer silently wraps wide literals: v[72'h1_0000_0000_0000_0003] becomes bit 3. Parse the literal at its own width. If any bit at or above 63 is set, clamp it to a sentinel out-of-range value, then send it through the same out-of-range path you use for other indices, so the simulator-specific rule (x, or the tool's quirk) applies there. Frontends like slang reject such indices by default (-Windex-oob) and accept them only when the warning is suppressed, so the case is rare but real.