EC_DOUBLE_ASSIGN_NEW_X hint shouldn't appear in issue #1031

[pefontana]

EC_DOUBLE_ASSIGN_NEW_X hint shouldn't appear in issue #1031

%{
from starkware.cairo.common.cairo_secp.secp_utils import SECP_P, pack

slope = pack(ids.slope, PRIME)
x = pack(ids.pt.x, PRIME)
y = pack(ids.pt.y, PRIME)

value = new_x = (pow(slope, 2, SECP_P) - 2 * x) % SECP_P
%}

This can happen because:

• The hint is duplicated with minor string differences in the whitelisted hint list. If this is the case, handle this string match in the cairo-rs HintProcessor.
• We use a different string from the one in the whitelisted hint list. If this is the case, fix the string match.