Float code cleanup related changes

[x] ivas_cpe_dec cleanup.
[x] ivas_core_dec local buffers cleanup.
[x] dirac dec cleanup.

EVS 26.444 BE test passes.

pytests results: 361 failed, 227 passed, 381 skipped

MLD scores:
Original inputs: (122 cases > 5)
5.055949 5.116346 5.133717 5.205395 5.281465 5.635546 5.687743 5.77246 5.812019 5.827425 5.828725 5.846702 5.968175 6.072145 6.186086 6.206511 6.239223 6.244739 6.270281 6.349464 6.408922 6.598248 6.623413 6.677552 6.795935 6.83956 6.857295 6.904842 7.080922 7.165194 7.45352 7.45352 7.497848 7.529704 7.62014 7.771643 7.844121 7.939482 8.167404 8.216558 8.274179 8.286527 8.304965 8.324407 8.486935 8.581776 8.666502 8.673138 8.684128 8.702198 8.830259 8.844512 8.886474 8.944175 8.977925 8.995053 8.995053 9.00578 9.019334 9.121075 9.181315 9.213806 9.223268 9.2742 9.275233 9.313997 10.302282 10.307885 10.513152 10.595121 10.818294 10.843693 11.242775 11.438915 11.460734 11.605155 11.689693 11.730725 12.147408 12.154493 12.196115 12.475451 12.64118 12.931603 12.960993 13.630015 13.651644 13.762701 13.928228 14.198871 14.313234 14.580093 14.733986 14.766648 14.856287 15.01375 15.032045 15.047781 15.163982 15.180505 15.210789 15.210789 15.854593 16.041946 16.338787 17.802933 18.28553 18.587318 18.706602 19.615063 20.915905 23.09226 23.125166 23.210155 23.210155 23.656136 27.571016 27.878029 28.358538 29.06115 36.126232 41.624199

+10dB scaled inputs: (227 cases > 5)
5.060941 5.122501 5.179455 5.181035 5.183616 5.219417 5.219417 5.223173 5.230988 5.238074 5.295208 5.324491 5.334821 5.370155 5.370911 5.381587 5.413538 5.470702 5.530519 5.601165 5.675697 5.738518 5.750943 5.834798 5.841172 5.843205 5.843205 5.84635 5.896245 5.936169 5.936633 5.970968 5.970968 6.005865 6.024678 6.103602 6.123783 6.187164 6.33073 6.35669 6.422366 6.43252 6.461218 6.463592 6.521821 6.546427 6.659053 6.869608 6.904323 6.962271 7.062504 7.136634 7.172103 7.178792 7.187855 7.249771 7.249771 7.376068 7.475472 7.480731 7.480826 7.63132 7.656866 7.675262 7.689881 7.792459 7.822392 7.825308 7.875839 7.92202 8.001102 8.103946 8.164176 8.21946 8.289465 8.666849 8.773835 8.799518 9.258256 9.283793 9.287988 9.371297 9.38784 9.390395 9.46368 9.557309 9.578907 9.578907 9.578918 9.580485 9.616096 9.657418 9.767278 9.834878 9.964149 10.060878 10.067425 10.111269 10.176598 10.287716 10.554173 10.950912 10.972899 10.980598 11.015555 11.18879 11.313582 11.366643 11.486061 11.520792 11.805201 11.839015 11.902574 12.124894 12.305219 12.335491 12.440291 12.558582 12.704875 12.752011 12.880072 12.99782 13.147717 13.159513 13.193845 13.389624 13.724923 13.739257 13.945606 14.061055 14.100877 14.454212 14.4547 14.593824 14.65421 14.65421 14.677289 14.729445 14.756527 15.006207 15.105474 15.191152 15.250995 15.325041 15.486865 15.731986 15.945988 15.950644 16.140497 16.190977 16.312601 16.346699 16.585825 16.647543 16.6908 16.841728 17.306362 17.786097 17.81809 18.129436 18.134777 18.216097 18.554369 18.563829 18.69655 18.87434 19.001526 19.001526 19.148188 19.314991 19.42897 19.48007 19.52066 19.640583 19.640583 19.715807 19.729355 20.261 20.488691 20.527447 20.79163 21.48329 21.899019 22.118731 22.727077 22.841728 22.841728 23.25248 23.32056 23.505434 23.609018 23.738111 24.116896 24.26866 24.308144 24.694593 24.923298 25.848694 26.81983 27.116436 27.395174 28.120453 28.679146 29.092422 30.572449 30.865534 30.932661 31.822306 32.291603 34.890053 35.000305 36.31105 36.422184 36.774063 37.17445 37.327656 39.70937 41.279297 42.11253 43.790993 47.318615 48.324764 51.694031 52.614151 56.342129 67.131119 67.179558

-10dB scaled inputs: (61 cases > 5)
5.013263 5.035575 5.105625 5.187019 5.206096 5.224868 5.272424 5.279836 5.282151 5.320052 5.385504 5.581379 5.587225 5.619368 5.855899 5.883981 5.961409 6.00611 6.080024 6.224255 6.240948 6.42071 6.524865 6.546113 6.549183 6.653874 6.764147 6.887078 6.947124 6.99308 7.085145 7.18956 7.241436 7.269883 7.271667 7.443463 7.710481 7.710481 7.866954 7.989997 8.169742 8.288192 8.466687 8.618037 8.692286 9.280319 9.420434 9.834721 9.846334 9.846334 10.077152 11.041007 12.612538 12.621989 14.86024 14.86024 15.163524 15.223334 15.714536 20.157457 23.66341