Wrap pointers to s2n-bignum functions - delocator fix

[nebeid]

Issues:

Resolves #ISSUE-NUMBER1
Addresses #ISSUE-NUMBER2

Description of changes:

Wrap pointers to s2n-bignum functions so that the delocator does not think they're local_target while they have :got: references.

Call-outs:

Testing:

On Graviton3, FIPS static build with gcc-11 which used to fail with

Building ASM object crypto/fipsmodule/CMakeFiles/bcm_hashunset.dir/bcm-delocated.S.o
FAILED: crypto/fipsmodule/CMakeFiles/bcm_hashunset.dir/bcm-delocated.S.o 
/usr/bin/gcc-11 -DBORINGSSL_FIPS -DBORINGSSL_HAVE_LIBUNWIND -DBORINGSSL_IMPLEMENTATION -DFIPS_ENTROPY_SOURCE_PASSIVE -Isymbol_prefix_include -I../include -Wno-newline-eof -Wa,--noexecstack -O3 -DNDEBUG -fPIC -MD -MT crypto/fipsmodule/CMakeFiles/bcm_hashunset.dir/bcm-delocated.S.o -MF crypto/fipsmodule/CMakeFiles/bcm_hashunset.dir/bcm-delocated.S.o.d -o crypto/fipsmodule/CMakeFiles/bcm_hashunset.dir/bcm-delocated.S.o -c crypto/fipsmodule/bcm-delocated.S
bcm.c: Assembler messages:
bcm.c:7811: Error: pc-relative address offset out of range
bcm.c:7813: Error: pc-relative address offset out of range
bcm.c:7815: Error: pc-relative address offset out of range

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license and the ISC license.

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 78.97%. Comparing base (cc9c9f0) to head (d1452b1).

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #2165      +/-   ##
==========================================
- Coverage   78.97%   78.97%   -0.01%     
==========================================
  Files         611      611              
  Lines      105552   105569      +17     
  Branches    14950    14949       -1     
==========================================
+ Hits        83361    83373      +12     
- Misses      21538    21542       +4     
- Partials      653      654       +1     

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[jakemas]

Confirmed CI is now passing with this change applied on #2148

[jakemas]

Created #2166 to test this fix.