[Mips] Call findMIPSABIDirSuffix() for MIPS targets only.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@195750 91177308-0d34-0410-b5e6-96231b3b80d8
[Mips] Do not detect a used MIPS toolchain. Build a path suffix for FSF
toolchain first and check the path existence. If the path does not
exist build and check a path suffix for Code Sourcery toolchain.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@195751 91177308-0d34-0410-b5e6-96231b3b80d8
[Mips] Merge two MIPS Code Sourcery toolchain tests into the single one.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@195752 91177308-0d34-0410-b5e6-96231b3b80d8
[Mips] Add support for nan2008 libraries and headers look up for Code
Sourcery MIPS toolchain.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@195753 91177308-0d34-0410-b5e6-96231b3b80d8
[Mips] Reduce number of FileCheck variables used in the tests.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@195754 91177308-0d34-0410-b5e6-96231b3b80d8
[Mips] Replace explicit argument handling by the single ArgList::AddLastArg() call.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@195755 91177308-0d34-0410-b5e6-96231b3b80d8