Handle LLDB_LIB_DIR on FreeBSD as on Linux

Diagnosed and tested by Mike Ma.
http://llvm.org/pr18191
Add decorator for FreeBSD test failure pr18522
Add decorator for failing FreeBSD test
Upgrade ConstantFP's negative zero and infinity getters to handle vector types.

Will be used soon.
InstCombine: Make the (fmul X, -1.0) -> (fsub -0.0, X) transform handle vectors too.

PR18532.
[Mips] Simplify calculations of relocations - replace scatterBits calls
by bitwise AND operator and remove redundant local variables.
[Mips] Emit ELF header for MIPS target. ELF flags set is mostly hardcoded.
Later we need to improve that solution and build a correct set of flags
by merging ELF flags from all input objects.
[Mips] Use explicit assembler instructions in the tests.
Remove decorators for now-fixed pr18191