Remove copy relocation and optimize locally defined symbol access

Remove copy relocation, add canonical function address and optimize locally defined symbol access:

1. All accesses to protected definitions are local access.
2. In executable, all accesses to defined symbols are local access.
3. All global function pointers, whose function bodies aren't locally defined, must use GOT.
4. All read/write accesses to symbols, which aren't locally defined, must use GOT.
5. Branches to undefined symbols may use PLT.

These should be enforced by

1. Compiler: Add a compiler option, -fsingle-global-definition.

• Implemented on users/hjl/pr35513/master branch: https://gitlab.com/x86-gcc/gcc/-/tree/users/hjl/pr35513/master

2. Binutils:

• Assembler: Add a marker to indicate that relocatable output requires such a feature to work correctly.
• Linker: Add a marker by merging markers on all relocatable inputs to indicate that the linker output requires such a feature to work correctly.
• Implemented on users/hjl/property/master branch: https://gitlab.com/x86-binutils/binutils-gdb/-/tree/users/hjl/property/master

3. ld.so: Scan the marker on all components, the executable and its dependency shared libraries.

• When performing symbol lookup for references in an object without single global definition:
• Disallow copy relocations against protected data symbols in an object with single global definition.
• Disallow non-zero symbol values of undefined function symbols, which are used as the function pointer, against protected function symbols in an object with single global definition.
• Implemented on users/hjl/single-global/master branch: https://gitlab.com/x86-glibc/glibc/-/commits/users/hjl/single-global/master