Template patchELFPHDRTable, rewriteNoteSections, markGnuRelroSections,
and discoverStorage to support both ELF32LE and ELF64LE binaries.
Previously these functions were hardcoded for ELF64LE, causing crashes
when processing 32-bit ELF binaries.
The RewriteInstance constructor now accepts ELF32LE objects in addition
to ELF64LE. The ELF_FUNCTION macro is reused (and moved earlier in the
header) to dispatch to the correct template instantiation.
These changes are preparation for adding support to hexagon architecture
in Bolt.
98ced6cfd0