[X86FixupLEAs] Hoist the calls to isLEA out of the 3 separate functions and put it in the basic block instruction loop. NFC
[X86FixupLEAs] Hoist the calls to isLEA out of the 3 separate functions and put it in the basic block instruction loop. NFC

Now need to check it 3 different times. Just do it once at the top of the loop.

git-svn-id: 0ff597fd157e6f4fc38580e8d64ab130330d2411@359658 91177308-0d34-0410-b5e6-96231b3b80d8

apple/swift-llvm,GPUOpen-Drivers/llvm,llvm-mirror/llvm,llvm-mirror/llvm,llvm-mirror/llvm,GPUOpen-Drivers/llvm,apple/swift-llvm,apple/swift-llvm,GPUOpen-Drivers/llvm,apple/swift-llvm,GPUOpen-Drivers/llvm,llvm-mirror/llvm,apple/swift-llvm,GPUOpen-Drivers/llvm,llvm-mirror/llvm,GPUOpen-Drivers/llvm,apple/swift-llvm,apple/swift-llvm,llvm-mirror/llvm,llvm-mirror/llvm,GPUOpen-Drivers/llvm,llvm-mirror/llvm,apple/swift-llvm,GPUOpen-Drivers/llvm,llvm-mirror/llvm